help pleeease!

I know this is really bad, and I shouldn't be doing this; but once in a while, I check on my bf's Facebook inbox. And today, I found out he talks to the girl he used to fuck in Venezuela, and he talks dirty to her. My heart broke. I know you'll say i'm the one responsible of my own pain, but please, I need help with this. Should I tell him I saw what he did? (Because I also discovered he erases his conversations)