I had sex a few days ago with an unknown sexual history (says she's clean - but I don't know her = unknown background). First time we had sex it was with a condom. Before having sex the second time with a condom, I did make one fully penetrated stroke into her, and then pulled out to put a condom on. I mean, I bottomed out in her, but this penetration was probably a 3 second ordeal. Quantifying these risks I understand is an imperfect science, but this act occurred outside of my marriage, and I'm trying to figure out if I should go get tested for chlamydia or other NGUs. Thanks.