What is a sexual relationship?

A sexual relationship is any relationship between two or more people that includes sexual activity. It could be a one-off hook-up, a friends with benefits arrangement or a long-term partnership. Some sexual relationships involve strong feelings, and some don’t.

Sexual activity isn’t just penetrative sex. It includes:

• vaginal and anal sex
• oral sex
• touching each other’s genitals, including genital skin-to-skin contact
• sharing sex toys

All of these can pass on some STIs. That’s why it helps to think about your sexual health, whatever kind of relationship you’re in.

Every sexual relationship needs consent. The law in England and Wales says a person consents if they agree by choice and have the freedom and capacity to make that choice. In practice, this means:

• You can change your mind and stop at any time, even partway through.
• Being in a relationship with someone, or having had sex with them before, doesn’t mean they’ve agreed this time.
• Someone who is asleep, unconscious, or too drunk or high to understand what’s happening can’t consent.
• The age of consent is 16 across the UK.

A healthy relationship should never leave you feeling scared or controlled. If a partner puts you down, cuts you off from friends and family or tells you where you can go and who you can see, you can get confidential support. In England, women can call the National Domestic Abuse Helpline, run by Refuge, on 0808 2000 247, at any time of day or night. Men can call the Men’s Advice Line on 0808 8010 327. In an emergency, call 999.

There’s no right or wrong type of sexual relationship, as long as everyone involved agrees to it. Common types include:

• Casual sex or hook-ups: sex without the expectation of a relationship, sometimes with someone you’ve just met.
• Friends with benefits: friends who have sex without being in a romantic relationship.
• Monogamous relationships: two partners who only have sex with each other.
• Open relationships: a couple who agree that one or both of them can have sex with other people.
• Polyamory: having more than one romantic or sexual relationship at the same time, with everyone’s knowledge and agreement.

Some people choose not to have sex at all, for a while or for good. That’s a valid choice too.

Your risk of catching an STI depends less on the type of relationship and more on a few things:

• how many partners you have, and how many partners they have
• whether you use condoms and dental dams
• whether you and your partners get tested regularly

If you or your partners have other partners at the same time, an infection can pass from one person to the next. This can happen in casual, open and polyamorous relationships, and in a monogamous one if someone has sex outside it.

A monogamous relationship is low risk for STIs if you both test negative before you stop using condoms, and neither of you has sex with anyone else. But many STIs cause no symptoms, and a standard screen doesn’t usually check for every infection, such as Herpes. So a partner can have an infection without knowing it. Read more in “Can you get an STI in a relationship even if no one’s cheated?”

Talking about sexual health can feel awkward, but it gets easier with practice. Try to have the conversation before you have sex, rather than in the heat of the moment. You could talk about:

• when you each last had an STI test, and your results
• using condoms for vaginal and anal sex, and condoms or dental dams for oral sex
• contraception, if pregnancy is possible
• what you’re both comfortable with, and what you’re not
• whether either of you has other partners

Keep talking as your relationship changes. If you decide to stop using condoms, get tested together first. Read more in “Should we get tested before having sex? How to talk to a new partner”

Condoms are the best way to protect yourself and your partners from HIV and other STIs. There are other ways to protect your sexual health too:

• PrEP (pre-exposure prophylaxis): a medicine that lowers the risk of getting HIV for people at higher risk. It doesn’t protect against other STIs.
• The HPV vaccine: it helps protect against genital warts and cancers caused by HPV. It’s offered to children aged 12 to 13, and men aged 45 or under who have sex with men can also have it.
• The Hepatitis B vaccine: it’s recommended for people at higher risk, including people who change sexual partners often, gay, bisexual and other men who have sex with men, and sex workers.
• A vaccine for Gonorrhoea: since August 2025, England has offered a vaccine that helps protect against Gonorrhoea, mainly to gay, bisexual and other men who have sex with men at higher risk.

Regular testing matters too. UK guidance recommends an STI test at least once a year and after a new partner if you’re sexually active, and every 3 months if you’re at higher risk, for example if you have several or anonymous partners.

Get tested after sex without a condom with a new partner, and if you notice symptoms such as unusual discharge, pain when you pee, or sores, blisters or lumps around your genitals. If you’re starting a new relationship and want to stop using condoms, testing together gives you both peace of mind.

Better2Know offers:

• Full Screen: tests for Chlamydia, Gonorrhoea, Hepatitis B, HIV, Mycoplasma, Syphilis and Ureaplasma, 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.
• 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.
• Confidence Screen: the Full Screen plus throat and anal swabs for Chlamydia and Gonorrhoea, with results in 5 days. It is designed for gay and bisexual men.

Not sure which test you need? Our Patient Care Team is available 24/7 on 020 7099 0955. Read more in “Which STI test do I need? How to choose the right test after a new partner”

What’s the difference between a sexual and a romantic relationship?

A sexual relationship includes sexual activity, while a romantic relationship is about emotional closeness and attraction. Many relationships are both, but you can have one without the other, as in a friends with benefits arrangement.

Do you need STI tests if you’re in a monogamous relationship?

It’s a good idea to test together at the start, before you stop using condoms. After that, if you both only have sex with each other, the risk of catching a new STI is low. Read more in “Do you need STI testing if you’re in a monogamous long-term relationship?”

Can you get an STI without penetrative sex?

Yes. Oral sex, genital skin-to-skin contact and sharing sex toys can all pass on some STIs, such as Herpes, HPV, Syphilis, Chlamydia and Gonorrhoea. Read more in “7 ways you can catch an STI without having sex”

A sexual relationship can be casual or committed, with one partner or several. Whatever works for you, it should be built on consent, honesty and respect.

The type of relationship matters less than what you do to protect each other. Use condoms, talk openly and get tested when you have a new partner. 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 31 May 2024 and was last updated on 30 September 2026.

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

Sources

1. Brook, Sex and consent, updated 29 September 2026. https://www.brook.org.uk/your-life/sex-and-consent/
2. Sexual Offences Act 2003, section 74 (England and Wales). https://www.legislation.gov.uk/ukpga/2003/42/section/74
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5. NHS, Condoms, reviewed 26 January 2024. https://www.nhs.uk/contraception/methods-of-contraception/condoms/
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10. UK Health Security Agency, Sexually transmitted infections and screening for chlamydia in England: 2025 report, 2 June 2026. https://www.gov.uk/government/statistics/sexually-transmitted-infections-stis-annual-data-tables/sexually-transmitted-infections-and-screening-for-chlamydia-in-england-2025-report
11. NHS, About pre-exposure prophylaxis (PrEP), reviewed 10 March 2023. https://www.nhs.uk/medicines/pre-exposure-prophylaxis-prep/about-pre-exposure-prophylaxis-prep/
12. NHS, HPV vaccine, reviewed 1 September 2023. https://www.nhs.uk/vaccinations/hpv-vaccine/
13. NHS, Hepatitis B vaccine, reviewed 19 March 2024. https://www.nhs.uk/vaccinations/hepatitis-b-vaccine/