I find myself in quite a predicament. I was invited to a party during which the host and friend got quite drunk. There were a lot of people and I wasn't with him the whole time. At some point in the night he started to brag to a couple of guys and myself about some "feats" of the evening. Most of them were ok except one. He told us that "[he] winnie the poohed a girl this evening". Now the major problem is that he has a girlfriend and she was not at the party.
Why am I posting this here? First of all he is orthodox (I'm fighting as hard as possible not to put quotes around it), goes to church from time to time, has orthodox relatives. His girlfriend is orthodox, quite pious.
Now I do not know what to do. This is I think the second time this friend cheats. I'm also resisting the urge of writing "friend". He has this habit of exploiting people to satisfy his personal needs. And I have the feeling he told us this so that it is less of a burden for him and so that we are complicit to his fault. I believe that all the previous things I mentioned about him are only masks. I don't know why he wears them, but I have seen glimpses of good in him.
I haven't seen the girlfriend since, but I know I will at some point, and to be honest I'm not even sure if me seeing her matters. He was cheated on by someone who doesn't show an ounce of regret; I feel like she should now. She seems like a nice person, not deserving any of this.
So I guess my question is what should I do? Each time I will see her, I will essentially be lying to her. In addition to the fact that she's being lied to by her boyfriend.
I'd appreciate any advise.