My Partner Has an STI: What to Do, Step by Step
An infection doesn't always mean someone cheated. What helps most is staying calm, getting tested together, being treated together and planning prevention as a team.
Key points
- Many infections have no symptoms and can stay hidden for a long time, so it is often impossible to say who got it first or when.
- Step one is to get tested together, both complete treatment, and avoid sex until a doctor says it's safe.
- If it's HIV and you had a risk within the last 72 hours, ask for PEP urgently.
"My girlfriend just told me she tested positive for herpes. Should I be angry?" Questions like this come with shock, fear and doubts about faithfulness. I'd like you to take a deep breath first, then go step by step, because what you do in the first few hours affects both your health and your relationship.
An infection doesn't always mean someone cheated
Many sexually transmitted infections (STIs) have no symptoms or can stay hidden for months to years.
| Infection | Why you can't tell when it was caught |
|---|---|
| Herpes (HSV) | Many people are infected without ever having symptoms, and can shed the virus even without sores. A first outbreak may happen long after infection. |
| HPV and genital warts | Extremely common; the virus may stay silent for months or years before warts appear or it is detected. |
| Chlamydia and gonorrhoea | Often symptom-free in women, and in the throat or rectum. |
| Syphilis | The early sore is often painless and may be somewhere you can't see. |
| HIV | Can cause no symptoms for many years. |
| Scabies and pubic lice | Can spread through close contact or shared items. |
So in many cases, we may never know who had it first, and a test result is not proof of cheating.
What to do first: 6 steps
- Stay calm and listen first. Thank your partner for being brave enough to tell you. Being honest about this isn't easy.
- Ask exactly which infection was found. Each one is managed differently.
- Get tested yourself, even if you have no symptoms. Read the 14-pathogen PCR STI test and STI testing for couples.
- Make sure both of you complete treatment. If only one of you is treated, the infection can pass back and forth ("ping-pong infection").
- Pause sex for now. For chlamydia and gonorrhoea, this is generally at least 7 days after both of you have finished treatment and symptoms have gone, or as your doctor advises.
- Get retested as scheduled. For example, retesting at about 3 months is recommended after chlamydia and gonorrhoea, and syphilis needs blood tests followed up over time.
- 1Stay calm, listenThank them for telling you, then ask which infection it is
- 2Get tested yourselfEven without symptoms, as many infections are silent
- 3Both treated fullyTo prevent passing it back and forth (ping-pong infection)
- 4Abstain from sexChlamydia, gonorrhoea: at least 7 days after both finish treatment
- 5Retest as scheduledChlamydia, gonorrhoea at about 3 months; syphilis by follow-up blood tests
A result is not proof of cheating. In many cases you can't know who had it first.
Guidance for common infections
Herpes is not a serious disease in healthy adults. Antiviral medication shortens outbreaks, and daily suppressive medication taken by the partner with the virus cuts the chance of passing it on by roughly half, together with condoms and avoiding sex during outbreaks. Read herpes: can it be cured and how to live with it and a real patient story, I have herpes.
HPV. Most people's bodies clear the virus on their own within 1–2 years. The HPV vaccine is still useful to protect against other types, and women should keep up with cervical cancer screening as scheduled.
Syphilis, gonorrhoea and chlamydia can be cured with antibiotics prescribed by a doctor, but you can catch them again.
HIV
- If you recently had condomless sex with a partner who isn't yet on treatment, within 72 hours, ask urgently for PEP (post-exposure prophylaxis). The sooner the better.
- If your partner takes antiretroviral treatment and has a consistently undetectable viral load, they do not transmit HIV through sex. Read U=U.
- The HIV-negative partner can consider PrEP, especially while the other partner has just started treatment.
How to talk without breaking your relationship
- Separate health from trust. Deal with testing and treatment first, then talk about the relationship once you're both calm.
- Use "I feel..." sentences, such as "I'm shocked and scared" instead of "Who did you get this from?"
- If there really was infidelity, that's a relationship issue to discuss separately, and you may want a counsellor's help. Read common couple problems.
- Don't stigmatise. Guilt and shame stop people from getting tested and from telling their partners. Read guilt after an STI, and not blaming each other as a couple.
Love doesn't lose to infections. It tends to lose to blame and silence. Going for treatment hand in hand is better than pushing each other away.
Planning prevention together from here
- Use condoms and a suitable lubricant.
- Get regular STI tests based on your risk.
- Get vaccinated where vaccines exist, such as HPV and hepatitis B.
- Consider PrEP for HIV, and ask a doctor about doxy-PEP if you are in a group the guidelines recommend it for.
When to see a doctor right away
- You had a possible HIV exposure within the last 72 hours.
- You have sores, blisters, a rash, unusual discharge or pus, or burning when you urinate.
- You have lower abdominal pain with fever (in women this may be pelvic inflammatory disease).
- You are pregnant or planning a pregnancy, because some infections can pass to the baby.
At Dr. Kris Clinic in Surat Thani, we test and care for couples together, privately and without judgement, covering testing, treatment, prevention and talking about the relationship after you get results. Online consultations are available across Thailand, and we offer English-speaking consultations.
Related case stories from Dr. Kris
Dr. Kris Case: "I Have Herpes" — Telling a Partner and Living With ItHerpes can be managed with medicine, condoms and honest, blame-free disclosure to a partnerMedicines and services your doctor may consider
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Frequently asked questions
My partner has herpes. Does that mean they cheated?
Not necessarily. Herpes is very common, many people have carried it for a long time without symptoms, and a first outbreak can happen years after infection, so it's impossible to say when or from whom it was caught.
If my test is negative, does that mean I'm not infected?
It depends on the infection and when you were tested. Some infections have a window period when tests can't yet detect them. Your doctor may arrange a retest, and in some cases recommends treatment alongside your partner even if your result is negative.
Do I need to tell my ex?
You should tell sexual partners from the period your doctor advises so they can get tested and treated. If you don't feel able to tell them yourself, ask your doctor about safe ways to notify them.
My partner has HIV but is undetectable on treatment. Do we still need condoms?
HIV is not transmitted through sex under U=U, but condoms still help protect against other STIs and unplanned pregnancy.
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References
- Workowski KA, et al. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR Recomm Rep. 2021;70(4):1-187.
- Corey L, et al. Once-daily valacyclovir to reduce the risk of transmission of genital herpes. N Engl J Med. 2004;350(1):11-20.
- Rodger AJ, et al. Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER2). Lancet. 2019;393(10189):2428-2438.
- Tuddenham S, Hamill MM, Ghanem KG. Diagnosis and treatment of sexually transmitted infections: a review. JAMA. 2022;327(2):161-172.
This article is for education and does not replace diagnosis or treatment by a doctor. If you have symptoms or concerns, please see a doctor.
