Since my last negative STI screen I had two sexual partners, both of which I asked to complete an STI screening prior to having unprotected sex, which was negative. My partner last had unprotected sex 6 months prior to us having unprotected sex.

After the first episode of unprotected penetrative/oral sex with my current partner I noticed an increase in vaginal discharge for 2-3 days and had a very bad sore throat. My partner is asymptomatic. 

I am a medical student on placement in gynaecology and have examined patients with gonorrhoea in the hospital. I also regularly wax my vulva and noticed my aesthetician "double dips".

Although men are only asymptomatic in 10% of cases and false negatives are rare, given that non-sexual transmission is also very rare and all of my partners have tested negative, what is the probability that my current partner was asymptomatic but had gonorrhoea with a false negative test?

Your initial test result is atypical; "borderline" is not an official or standard possible test outcome. If the test was weakly positive, you can assume you were infected. Lab error do occur but are rare, and you should have been treated after that result. But apparently not, since your test two weeks later was definitely positive, right? I certainly hope you were treated then! You should have been given an injection of ceftriaxone 500 mg, usually followed by a week of doxycycline -- although that part is optional if you tested negative for chlamydia.

I'm not sure I understand the timing of your gonorrhea diagnosis and when your two partners were tested. Standard practice is to always treat partners when someone has gonorrhea, even if they test negative. Can you give more information about exactly when you had sex with each one and whether they were treated? What treatment(s) did you receive?

Asymptomatic gonorrhea in men is a lot less common than 10%. It's under 1% who do not get symptoms. (In case you are interested, here is the most comprehensive study ever done on asymptomatic gonorrhea in men. Note the first author! https://pubmed.ncbi.nlm.nih.gov/4202519/

Your current partner probably should be treated -- better safe than sorry.

I hope these comments are helpful. I look forward to hearing about your treatment(s).

HHH, MD

My question is mainly about how I got infected - all my partners have tested negative and are asymptomatic. Where did it come from?! 

Thank you :)

Some STD infections, including gonorrhea, remain a mystery. In the large majority of couples with histories like yours, one partner or the other is not being truthful about sex with other partners. This is especially true for gonorrhea, for which the tests are highly accurate and very longstanding infections (months or years) are uncommon. You're the only one who can judge this, but you might need a heart-to-heart discussion with him. Or consider whether you had another exposure in the last couple of months that you don't remember or spaced out on. Finally, although the tests are very good, they aren't perfect:  false positive results are rare but do occur from time to time.