There is an old saying - "When you marry a man who cheats on his wife, you marry a man who cheats on his wife."
However, none of us is the man, wife or girlfriend in this senario. He could be in the worst marraige known to man, his wife could have been cheating on him, the baby could be someone other than the husband's. We don't know.
My best advise is for the OP to MYOB, but be there if it turns out badly for your friend. An never say "I told you so". Say "I'm sorry it wasn't what your thought, or he was a liar and a cheat". Saying I told you so makes the situation about you, not your friend.
If that doesn't tell you something about the guy, I don't know what does. Who would wait four years to leave his wife, then wait until there is a newborn in the house to leave? A scumbag, that's who. Obviously the guy has problems with responsibility. Who wants to be involved with someone like that? Yes, if he will leave his wife during this time of need, he will have no qualms about leaving your friend when she needs him. What does he have to show that can convince her otherwise? Actions speak louder than words. And as my mother would say, run, far and fast. The best you can hope for is that he will at least do right by his child, if not by the MOTHER of his child. Though it sounds like if your friend leaves him, he will just find someone else to help him avoid his responsibilities.
