<human>: Can you provide a brief rundown of the text in within 3 sentences?

My boyfriend and I have currently been dating for a year and a half.  We have never had any major issues, and we are both very committed to the relationship.

However, last night we got into a fight.  The fight was about how much time we spend together.  We usually see each other for a little bit every day.  I like to see him a little more than he does, and he has admitted before to wanting more free time away from each other, which is a thing I understand and am currently trying to work on.

Tonight, while we were hanging out, I got a message from a girl he had a short fling with before meeting me.  The message stated that she had received a snapchap of his dick last night, and thought I would like to know.  I immediately asked him about it. He immediately confessed to it and was extremely apologetic about it.

This is completely out of character for him.  Like seriously, biased opinion aside, he is one of the most respectable people I know.  And I know he is committed to me.  Which is why I'm having a very hard time understanding why he would do something like this.  I never thought anything remotely like this would happen, and I have absolutely no idea  what to do about it.

I don't want to leave him because of this, but I really don't think I can trust him the same way again.  I also don't want to be seen as being too accepting, giving him the idea he can get away with something like this again.
<bot>: My boyfriend sent a snapchap of his dick to another girl last night and I have no idea what to think about it.