How to tell your ex you have an STI

Usually, if you had sex with them recently enough. The NHS says that if tests show you have an STI, you should tell your current partner and any ex-partners, so they can get tested and treated too.

How far back you need to go depends on the infection. For example, UK guidelines suggest telling partners from the last 6 months for most people with Chlamydia, and from the last 3 months for most people with Gonorrhoea. For Syphilis and HIV, it can be much longer. Whoever treats you can help you work out who needs to know.

Herpes and genital warts are different. UK guidelines don’t require partners to be told, although telling partners about Herpes is encouraged, and current partners of someone with genital warts may want to get checked.

You have two options, and both are fine:

• Tell them yourself, face to face, by phone or by message.
• Ask the service that treats you to contact them. They can usually do this without giving your name.

Telling them yourself means you can explain and answer their questions. Letting someone else do it can feel easier if you’re not on good terms, or you’d rather not hear from them again. Read more in “Can you tell a partner anonymously they need an STI test?”

Brook says there are no rules about how to tell someone. It depends on how well you know them and what you feel comfortable with. With an ex, short and factual usually works best. You could send something like:

“Hi, sorry to message out of the blue. I’ve tested positive for Gonorrhoea, and as we slept together in the last few months, you could have it too. It often has no symptoms and it’s treatable, so it’s worth getting tested.”

It helps to:

• name the infection, so they know which test to ask for
• stick to the facts, rather than going over the relationship
• give them time to take it in and ask questions

If you decide to meet, Brook suggests choosing a place where you feel safe and comfortable, ideally with a way to leave if their reaction makes you feel unsafe.

Your ex may be angry or upset, or assume you cheated or that you gave it to them. It helps to remember:

• Many STIs cause no symptoms, so either of you could have had it for months, or even years, without knowing.
• A test can’t show when someone caught an infection, or who from. With Herpes and genital warts, it may never be possible to know.
• Telling them is the right thing to do. It doesn’t mean you’ve done anything wrong.

How they react isn’t your responsibility. Brook says that if someone reacts with fear or judgement, it’s not your fault and not something you need to manage. You don’t have to keep talking if the conversation turns nasty. Read more in “Can you get an STI in a relationship even if no one’s cheated?”

It’s natural to feel angry if you think your ex passed the infection to you. But it’s often impossible to know for sure, and they may not have known they had it. Telling them still matters, as they may need treatment and could pass the infection on to someone else.

If you’re still having sex with your ex, avoid sex until you’ve both finished treatment and whoever treats you says it’s safe, or you could pass the infection back and forth. If your ex has told you they have an STI, read “My ex told me they have an STI. Which test is right for me?”

If your ex was controlling or abusive, or you’re worried about how they’ll react, you don’t have to contact them yourself. Ask the service that treats you to tell them without naming you.

If you’re in danger, call 999. You can also get free, confidential support from:

• England: the National Domestic Abuse Helpline for women on 0808 2000 247, or the Men’s Advice Line for men on 0808 8010 327
• Scotland: Scotland’s Domestic Abuse and Forced Marriage Helpline on 0800 027 1234
• Wales: Live Fear Free on 0808 80 10 800
• Northern Ireland: the Domestic and Sexual Abuse Helpline on 0808 802 1414
• LGBT+ people: Galop’s National LGBT+ Domestic Abuse Helpline on 0800 999 5428

In England and Wales, there’s no legal requirement to tell a partner you have an STI. But passing on a serious infection, such as HIV or Herpes, recklessly or on purpose can be a crime. Scotland and Northern Ireland have their own laws and prosecution services. Read more in “Herpes and the law: can you be prosecuted for passing it on?”

If your ex has an STI, or you want a full check after your own diagnosis, Better2Know offers:

• Full Screen: tests for 7 infections, including Chlamydia, Gonorrhoea, HIV, Syphilis and Hepatitis B, from 28 days after sex, with results in 3 days (5 days for the 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. You can book it at one of our clinics or order a home test kit.
• Platinum Screen: tests for 12 infections, including Herpes 1 and Herpes 2, 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.

Can I tell my ex by text?

Yes. Brook says a message or voice note can work for a previous partner, depending on your relationship. Name the infection and suggest they get tested.

What if my ex doesn’t reply?

You’ve done your part by telling them. If you’re worried they haven’t seen the message, the service that treats you may be able to contact them for you without naming you.

Do I need to tell an ex from years ago?

Usually not. For most STIs, UK guidelines look back weeks or months. For some, such as Syphilis that has been there a long time, or HIV, it can be years, and whoever treats you will advise who to contact.

Telling an ex you have an STI is awkward, but it’s a kind thing to do. A short, factual message is enough, and if you’d rather not contact them, the service that treats you can usually do it without naming you. Either way, it means they can get tested and treated, and it helps stop the infection spreading.

If you or your ex need a test, 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.

Not in the UK? Choose your country from the selector at the top of the page for local tests and prices.

This article originally appeared on 28 December 2013 and was last updated on 1 October 2026.

This article is general information and not a substitute for personal medical advice.

Sources

1. NHS, Sexually transmitted infections (STIs), reviewed 13 May 2024. https://www.nhs.uk/conditions/sexually-transmitted-infections-stis/
2. Brook, How to tell someone you’ve got an STI, updated 21 August 2025. https://www.brook.org.uk/your-life/talking-to-people-about-stis/
3. British Association for Sexual Health and HIV, UK national guideline for the management of infection with Chlamydia trachomatis, 2026. https://www.bashh.org/_userfiles/pages/files/national_guideline_for_the_management_of_infection_chlamydia_trachomatis_2026.pdf
4. British Association for Sexual Health and HIV, UK national guideline for the management of infection with Neisseria gonorrhoeae, 2025. https://www.bashh.org/resources/136/gonorrhoea_guideline_2025
5. British Association for Sexual Health and HIV, UK guidelines for the management of syphilis, 2024. https://www.bashh.org/_userfiles/pages/files/syphilis_2024.pdf
6. British Association for Sexual Health and HIV, British HIV Association, Society of Sexual Health Advisers and National AIDS Trust, HIV partner notification for adults: definitions, outcomes and standards, 2015. https://www.bashh.org/_userfiles/pages/files/resources/hiv_partner_notification_standards_2015.pdf
7. British Association for Sexual Health and HIV, UK national guideline for the management of anogenital herpes, 2024. https://www.bashh.org/_userfiles/pages/files/pateletal2024britishassociationofsexualhealthandhivuknationalguidelineforthemanagementofanogenital.pdf
8. British Association for Sexual Health and HIV, National guideline for the management of anogenital warts in adults, 2024. https://www.bashh.org/_userfiles/pages/files/resources/agw_2024.pdf
9. NHS, Genital herpes, reviewed 27 June 2023. https://www.nhs.uk/conditions/genital-herpes/
10. NHS, Genital warts, reviewed 10 July 2023. https://www.nhs.uk/conditions/genital-warts/
11. NHS, Chlamydia, reviewed 24 October 2024. https://www.nhs.uk/conditions/chlamydia/
12. NHS, Getting help for domestic violence and abuse, reviewed 23 June 2026. https://www.nhs.uk/live-well/getting-help-for-domestic-violence/
13. Refuge, National Domestic Abuse Helpline, accessed 1 October 2026. https://www.nationaldahelpline.org.uk/
14. Respect, Men’s Advice Line, accessed 1 October 2026. https://mensadviceline.org.uk/
15. Scotland’s Domestic Abuse and Forced Marriage Helpline, accessed 1 October 2026. https://sdafmh.org.uk/
16. Welsh Government, Live Fear Free, accessed 1 October 2026. https://www.gov.wales/live-fear-free/contact-live-fear-free
17. nidirect, Domestic and Sexual Abuse Helpline, updated 18 June 2026. https://www.nidirect.gov.uk/articles/domestic-and-sexual-abuse-helpline
18. Galop, Helplines, accessed 1 October 2026. https://galop.org.uk/get-help/helplines/
19. Crown Prosecution Service, Intentional or reckless sexual transmission of infection, updated 29 March 2023. https://www.cps.gov.uk/legal-guidance/intentional-or-reckless-sexual-transmission-infection