I was at a party and got really drunk that I can't even remember what I was doing that night and all I wanted to to do was fall asleep. But this one guy I knew got in bed with me too and I remember we did some stuff and he tried having sex with me. I can't exactly remember if he did get it in. But I remember that in the process of him trying it was hurting really bad. Is there a way that I can find out if we had intercourse or he did get it in me?

Me and my partner have been together for 5 months now. I have just recently been tested positive for an STI (chlamydia). My partner and I have never used condoms because I am on the pill. My partner went and got himself tested and his results came back negative. How is that possible?