Thought I would share my story, that combines perhaps bad luck and a bit of stupidity.
I decided to visit a WG for the first time two years ago. After spending many a dark hour making plans (I wish I had known about this site at the time), I met a girl, had a great time, RO, OWO, protected penetration, CIM. Feeling like a sex god, I slept with my wife that night, totally against my earlier plan. Then continued the spree with three more WGs over the next week.
About a fortnight later I had to admit to myself that the end of my cock was stinging badly, and that I had definitely caught something.
A trip to the GUM clinic confirmed that I had NSU. However at the time, chlamydia was not ruled out until the full test results came back 2 weeks later. While even the GUM clinic said that NSU is not necessarily sexually transmitted, I have come to my own conclusions.
In the end I was able to deny everything to my wife and rescue my marriage. With an NSU you can blame it on new shower gel, banging your cock in a door etc. We both had a dose of antibiotics and all is back to normal now. Well, I say normal, I still spend way too much time thinking about and visiting WGs.