<human>: Me (m 20) and my girlfriend (f 20) have been together on and off for over a year and a half.  Our relationship was very rocky at first.  In the beginning we were both very immature about relationships and partied and drank a lot, leading to many regrets.  Since then we've gotten most of our partying phase out and did some growing up, but my girlfriend still likes to go to parties occasionally.  I'm more of a "chill with a few friends" type of person, but my girlfriend doesn't mind going to bigger parties.  Early in our relationship we didn't really take commitment too seriously and drunkenly cheated on each other a few times.  

Since our personalities mix together so well and we're in love we both decided to stick it out with each other each time (not without some punishment though).  And since then we've strongly committed to each other and our relationship and I'd like to say I completely trust her, but I just can't.  She understands this and has limited herself to going to parties with available alcohol greatly.  I feel as though I'm a burden to her and I'm holding her back because I don't enjoy going to parties with her friends or even with her really.  And when I do tell her to just go by herself and put on a fake smile and tell her it's okay I worry myself almost sick that she's cheating on me with a guy or a girl.  And I also feel like she's going to meet someone better than me.  Its been a long time that she has cheated on me and I've forgiven her for it, but I just can't seem to shake it.  

I feel as though I'm broken and can't be fixed.  I don't want to be like this forever, its unhealthy for the both of us.  I don't want to break up with her either, she's my best friend and I can't imagine myself without her.  I hope someone can give me some advice to how they have or I can overcome this problem :(.

Can you condense the text into a few key points?
<bot>: – I struggle to trust my gf with going to parties by herself and feel like shes going to meet someone better than me.