I've been going out with a girl here at my school for the past six months. Last weekend I went home (out of state), and fooled around with an ex-girlfriend. She called me last night and told me that she might have an STI. She went to the doctor this week and told me she would let me know when she finds out for sure. We didn't use a condom.

My problem is, what should I tell my girlfriend? I really love her and don't want to ruin things because of this stupid fling I had. But I can tell she's annoyed that I've avoided her all weekend. I can't exactly tell her next time we get together that I don't feel like fooling around, but I don't know how long it will be before I know if I'm infected. And what do I do if I am? Help!

My friend has only been at college for two weeks, and she has already had sex with several guys. She is having safe sex, so it's not dangerous in that sense and she claims to be enjoying herself. However, it seems to me that such behavior is unhealthy and damaging to one's emotional state and reputation — but I'm not sure how to explain to her how I feel, or articulate what is wrong with her how she's acting. Do you think what she's doing is wrong, and if so, how should I confront her?