You can't really MAKE someone WANT to work on their marriage. That is entirely her choice. All you can do is work on YOU, and you can also lay out -- and learn to enforce -- your own boundaries of personal integrity.
I would assume that one of them is "I cannot live in a marriage where another man is sleeping with my wife in my own house."
One mistake that you made, that I would correct IMMEDIATELY, was leaving your own house. I would simply move back in, and when your wife says "What the hell do you think you are doing??!", say "I'm moving back into my own home." If she says "I can't live like this!" then say "I understand. If you want to leave, I certainly can't stop you, but I'm done inconveniencing myself, and distancing myself from my own son when I've done nothing wrong."
If she wants to call mediators, attys, etc., you can't stop her, but you can certainly stall and delay.
