I snooped on my husbands Facebook and confronted him

I found a private message to a girl sent a month ago at 2am saying "consider this a like on your picture, I can't actually like it because my wife will see it and get mad" I immediately confronted him via text message and he shrugged it off by saying that he was trying to make her feel good because her husband left her and her kid and that I am in the wrong for stalking his Facebook. I admit I am in the wrong but is it really his place to comfort another woman by complimenting her looks especially when it's uncalled for? should I feel guilty for snooping when he should feel worse for messaging someone else about a picture where their cleavage is hanging out of their blouse... I'm going to see him tonight when we get home from work and I'm in need of advice on how to talk to him/ deal with this situation. Please help.