Oh my gosh, I am so sorry but that is literally insane, how did you not know?! That means he is a massive, pathological liar who is living a double life, which is so creepy. You are basically in a movie right now, except it’s not fun because your feelings are actually hurt and you got tricked super bad.
You have to drop him immediately, like, yesterday. If he can hide a whole wife and kids from you, what else is he lying about? He is total trash for putting you in that position and making you the bad guy without you even knowing it. You absolutely cannot be the reason a family breaks up, even if he’s the one to blame.
Just block him on everything and pretend he doesn’t exist anymore. Don’t even bother confronting the wife because it’ll just be a bunch of screaming and drama that you don’t need. Wash your hands of this weirdo entirely and consider it a lucky escape that you found out his secret before you got in even deeper with him.