<human>: Can you condense the text into three sentences or less?

This is a throwaway, since I'm never sure who uses reddit and who doesn't.

A little backstory: I have been dating "Kevin" for sixth months. Everything has been great! He's mature, interesting, fun, and we get along very well. He likes my friends, I like his, and my family loves him. 

But there's one problem. A couple months ago, we were having a conversation about college and relationships, and I mentioned that two years ago, at a party in college, I got pretty drunk and hooked up with my best friend. It meant nothing, just one of those nights, and now she and I are still very close.

He CAN NOT get over it. He has started fights every time I bring her up, and it has gotten to the point where I don't think he'll be okay until I drop her as a friend.

I've let him know that this upsets me and will ultimately result in us having to part ways if we can't find a way to reconcile, but so far nothing has changed.

I guess my question is: is there anything I can do? This is the only problem in our relationship, but it's started to permeate everything. I'm not sure how we can get past it.
<bot>: My boyfriend can't get over the fact that I hooked up with one of my best girl friends TWO YEARS AGO in college. Don't want to drop the friend or the boyfriend. What do I do?