<human>: We have been together for 8 months, and he just told me that 3 months , right before Christmas, in when drunk he played a drinking game with old friends from his high school, and as some sort of dare he kissed a girl on the lips for like a second, so I mean it isn't really a big deal of kissing someone else. He has no history or any interest in the girl.

But now he said it out of the blue today, and he cried and everything, and I was at first really upset, now we are okay again, but I am not really sure what to think.

Otherwise he is the best boyfriend you can imagine, we never had a fight, he is the sweetest person, and he is very upset. Logically, this isn't much of a big deal, but I am still feeling a bit strange and want to ease my mind. Something has been broken a bit.. I don't want to talk about it with my friends or family, because I don't want to break something in their mind, because we are very serious. Am I ridiculously overreacting!

Could you distill the essence of the text into 1-3 sentences?
<bot>: bf kissed girl on the lips during drinking game, I don't think it is a big deal, but it still feel weird.