10 minutes read10 minutes readSummary:
- Tell your current partner and any recent partners as soon as you can. How far back you go depends on the infection, from a few weeks to 2 years or more.
- You can tell them yourself, in person or by message, or let them know without giving your name.
- Your partner needs a test even if they feel well. The Better2Know Full Screen tests for 7 infections from 28 days after sex, with results in 3 days.
A positive STI test result is hard enough. Working out how to tell your partner you have an STI can feel even harder. You might worry about how they’ll react, or what it means for the two of you. Most people who are diagnosed with an STI do tell their partners themselves, and there’s help if you’d rather not.
In this blog, we explain which partners to tell, what to say, what your partner needs to do next and what to do if telling them doesn’t feel safe.
Do you need to tell your partner?
Yes. The NHS advises telling your current partner or partners and any ex-partners, so they can get tested and treated as well. UK guidance gives four reasons:
- no symptoms: many STIs cause no symptoms, so your partner may have the infection and not know
- their health: untreated infections can cause lasting harm. Chlamydia and Gonorrhoea can lead to pelvic inflammatory disease and infertility
- your health: an untreated partner can pass the infection straight back to you
- other people: it helps stop the infection being passed on
It’s common for a partner to have the infection too. Going by UK guidelines, between a third and two thirds of the partners of people with Chlamydia test positive. For early Syphilis, 46% to 60% of partners who can be contacted also have it.
Which partners should you tell?
How far back you go depends on the infection. The British Association for Sexual Health and HIV (BASHH) sets a different look-back period for each one:
| Infection | Partners to tell |
| Chlamydia | Partners in the 6 months before your diagnosis. If you have symptoms in the penis, partners since 4 weeks before the symptoms started |
| Gonorrhoea | Partners in the 3 months before your diagnosis. If you have symptoms in the penis, partners since 2 weeks before the symptoms started, or your last partner if that was longer ago |
| Syphilis | The last 3 months for the first stage, when there’s a sore. Up to 2 years for the second stage, or for an early infection with no symptoms |
| Trichomonas | Current partners and any partners in the last 4 weeks |
| Mycoplasma genitalium | Current partners only |
| HIV | Partners since the time you were most likely infected, and in the 3 months before it |
| Herpes and genital warts | Formal notification isn’t required, but telling your partners is encouraged |
If you’re not sure who to tell, the doctor or health adviser treating you can help you work it out. You may not remember every detail, and that’s fine.
What to say when you tell your partner
There’s no single right way to do it. Brook, the sexual health charity, says it depends on how well you know the person and what you feel comfortable with. Telling them in person, by message or by voice note are all fine. Brook suggests:
- pick your moment: choose a time and place where you feel safe and confident
- prepare: the service that treats you can explain the infection, and you could work out what to say with someone you trust
- keep it simple: start by saying you have an STI, then ask if they have any questions
- talk about what happens next: their test, and what protection you’ll use
- look after yourself: plan to check in with a friend afterwards
You could say something like: “My STI test came back positive for Gonorrhoea. You might have it too, even if you feel fine, so you’ll need a test.”
How they react isn’t yours to manage. Brook says that if someone responds with fear or judgement, it’s not your fault, and you can leave and pick the conversation up later. You have nothing to be ashamed of or to apologise for. Read more in “How to tell your ex you have an STI”
What if you’d rather not tell them yourself?
You don’t have to do it alone, or in person. In the UK, letting partners know is called partner notification, and it’s a standard part of STI care. There are three ways to do it:
- tell them yourself: most people do
- give them a contact slip: a note from the clinic with details of the infection, but not your name, so they get the right tests and treatment
- let the service do it: a health adviser contacts your partner for you without giving your name, usually by phone and sometimes by letter, text or email
Your partner is told they’ve been in contact with an STI and need a test. They aren’t given any information about you. If you’ve only had one or two recent partners, though, they may still guess.
If you test with Better2Know, your patient area has a way to contact your partners. The message is already written, you can read it before it’s sent, and you can send it in your own name or anonymously. Read more in “Can you tell a partner anonymously they need an STI test?”
What should your partner do next?
Get tested, even if they feel well. Timing matters, because a test taken too soon can miss an infection:
- Chlamydia and Gonorrhoea: a test is reliable from 2 weeks after sex
- HIV: a lab blood test is reliable from 45 days
- Syphilis: a blood test in the first 3 months can miss it, so a repeat test is recommended
For some infections, UK guidelines say partners should be treated without waiting for a result:
- Trichomonas: partners are treated whatever their test shows
- early Syphilis: partners are offered treatment straight away, or a repeat blood test 12 weeks after their last contact
- Chlamydia: partners with symptoms are treated at the same time as they’re tested
For Gonorrhoea, most partners are now tested first and treated only if the test is positive. If your partner may have been exposed to HIV in the last 72 hours, they should get urgent medical care and ask about PEP, emergency medicine that can stop the infection.
The NHS advises not having sex, including oral sex, until you and your partner have both finished treatment. Otherwise you can pass the infection back and forth. Read more in “I took medication for my STI. Am I still contagious?”
Does a positive result mean someone cheated?
No. A positive test can’t show when you caught an infection or who you caught it from. Many STIs go unnoticed for months or years:
- Chlamydia: most people have no symptoms, and an untreated infection can last a year or more
- Gonorrhoea: the NHS says symptoms sometimes don’t appear until many months later
- Herpes: symptoms might not appear for weeks or even years, and a test can’t tell you how long you’ve had it
- HIV: you may have no symptoms for years
- HPV: the NHS says a positive result doesn’t mean your partner has had sex with someone else while you’ve been together
So it helps to leave blame out of the conversation. Neither of you may ever know who had the infection first. Read more in “Can you get an STI in a relationship even if no one’s cheated?”
If telling your partner doesn’t feel safe
Your safety comes first. If you’re worried about a violent or controlling reaction, you don’t have to tell your partner yourself. The National Institute for Health and Care Excellence (NICE) says other ways of telling partners may be needed for people at risk of domestic violence. A sexual health service can contact your partner for you without naming you, and if you tested with Better2Know, you can send an anonymous message from your patient area.
If you do decide to tell them yourself, you could send a message instead of meeting. If you do meet, Brook suggests choosing a place where you feel safe and can leave easily.
Support is free and confidential:
- National Domestic Abuse Helpline, for women: 0808 2000 247, open 24 hours a day
- Men’s Advice Line: 0808 8010 327, open Monday to Friday, 10am to 5pm
- Galop, for LGBT+ people: 0800 999 5428, open Monday to Friday
There are also 24-hour helplines in Scotland (0800 027 1234), Wales (0808 80 10 800) and Northern Ireland (0808 802 1414). If you’re in danger, call 999.
Do you have to tell your partner by law?
No. In England and Wales, there’s no legal requirement to tell a partner you have an STI. But passing on a serious infection intentionally or recklessly can be a crime. The Crown Prosecution Service (CPS) says cases have involved HIV and Herpes.
- The prosecution has to prove that the person knew they had the infection and actually passed it on.
- If a partner knew about the infection and agreed to the risk, that’s a defence to reckless transmission. It’s one more reason to tell them.
- Someone with HIV who has an undetectable viral load can’t pass it on through sex.
- In Scotland, recklessly putting someone at risk without passing the infection on can also be prosecuted, but only in exceptional circumstances.
This is general information, not legal advice. Read more in “Herpes and the law: can you be prosecuted for passing it on?”
Which test do you need?
If your partner needs a test, or you’d like to check for other infections, Better2Know offers:
- Full Screen: tests for 7 infections, including HIV, Syphilis, Hepatitis B, Chlamydia and Gonorrhoea, from 28 days after sex, with results in 3 days (5 days for the home test). You can book it at one of our clinics or order a Full Screen home test.
- Peace of Mind: if you want to test sooner, it checks for Chlamydia, Gonorrhoea and Syphilis from 14 days after sex, with results in 2 days.
- Platinum Screen: our most comprehensive STI screen. It tests for 12 infections, adding Hepatitis C, Herpes 1, Herpes 2, Trichomonas and Gardnerella to the Full Screen, from 28 days after sex, with results in 3 days.
If you test before 45 days, a negative HIV result needs a repeat test. A Syphilis test in the first 3 months after sex can miss the infection, so you may need a repeat test. Not sure which test you need? Our Patient Care Team is available 24/7 on 020 7099 0955.
FAQs
How soon should you tell your partner?
As soon as you can. UK guidelines say telling partners should be discussed when you’re diagnosed. The sooner your partner knows, the sooner they can be tested and treated, and the lower the chance that you catch the infection again.
What if your partner tests negative?
Check when the test was taken. A test in the first 2 weeks can miss Chlamydia and Gonorrhoea, and a Syphilis test in the first 3 months can miss the infection. For Trichomonas, partners are treated whatever their result.
Do you need to tell a partner about Herpes or genital warts?
UK guidelines don’t require formal partner notification for either. They do encourage telling partners, and BASHH says people who tell their partners about genital Herpes are less likely to pass it on.
Final thoughts
Telling your partner you have an STI is rarely an easy conversation, but it lets them get tested and treated, and it protects you from catching the infection again. Work out which partners to tell, keep the message simple, and remember that you can let a partner know without giving your name. A positive result doesn’t prove anyone cheated, and you have nothing to be ashamed of.
If your partner needs a test, they can book a Full Screen at a clinic near you or order a home test kit. Our Patient Care Team is available 24/7 on 020 7099 0955.
About this article
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This article originally appeared on 26 February 2021 and was last updated on 3 October 2026.
This article is general information and not a substitute for personal medical advice.
Sources
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