I've been going to the clinic on waller pretty much once a year for as long as I've lived in austin (about 10 years). I like the anonymity of not having to ask my family physician for an std screen. I don't recall having to provide an id, but that may be the case. If you're upper middle class, I doubt you'll be recognized by anyone. I don't mean to come off as rude, but it's basically a free clinic with a $20 copay (so basically free).
Best advice would be to quit fucking around on your SO. If you're incapable of that, make sure you're as safe as you can be. Wear the condoms, do your own visual inspection before anything happens (you can learn a lot from a few minutes between a woman's thighs)... oh and give me your SO's number for when she finds out and wants to get back at you!
j/k of course.