<human>: I just started dating a girl in the last month or so of the semester.
I like her a lot, but I worry sometimes about possible infidelties in the future. 

Before we dated, we were really good friends, and, during this period, I heard one or two stories (through mutual friends) about her hooking up with other guys while drunk/high. 

I know she'll be going to a lot of parties next year, ones that I won't be invited to/be able to get into. While I'm OK with her drinking and recreational drug usage, I'm worried about what she might do when under the influence. She promises that she will be faithful, but I am worried that something will happen, and I'll end up getting really hurt.

Are these legitimate concerns, or am I just pysching myself out? Do I have trust issues?

Can you condense the text into a few key points?
<bot>: Should I worry about infidelity if my SO has a history of hooking up with others when under the influence of drugs or alcohol?