<human>: Like the title says, i have been with my bf for 4 years. 3 years ago I was at a party and got blackout drunk, worse than ever before. My bf was not there, I was with friends (I have since moved away and don't see these friends and keep in contact with only a few of them). 

Anyway, the day after the party I was talking to a friend who was there and she said something about how I had kissed one of the boys there. I thought she must be joking about it and laughed it off. Then she said "you know you kissed P, right?" And I started to freak out, I had absolutely no memory of this happening. It's not a faint memory or anything, I still to this day have no memory of that happening, but I believe my friend - she was definitely not making it up and seemed shocked I didn't know. 

I told her to swear never to tell anyone, and contacted the guy and told him that I had no memory of it and I was in a good relationship and I wanted to pretend it didn't happen. He was fine with that & he agreed to just forget it. I've never talked about it since then and never told anyone, including my Bf. Since I don't remember it, it's usually easy to pretend it never happened, but I still feel so guilty sometimes. My bf is amazing and does not deserve me lying to him. If I told him though, it would ruin truly the most amazing thing in my life so far. I want to marry and have children with him, and I would never do anything to intentionally hurt him or us. And I don't think being drunk is an excuse for that stuff, but I just can't remember it - a big chunk of that night is just gone. Should I tell him? I don't know what it would do except hurt him, and I would NEVER dream of doing it again, and take special care to never get that drunk ever again.

Give me the gist of the text in a nutshell
<bot>: blackout drunk kissed another guy 3 yrs ago, should I tell my bf of 4 years? (Never gotten close to blackout drunk since then)