I remember the advice you got during Thanksgiving here and I can't believe you're still at the same place where you were. I cannot echo more what others have already said and Ginger just really broke it down for you.
I see a man in denial desperately clinging on to hope that some thing will turn this ship around. Where is your self-respect man? Seriously - she is messing around with a family member. Why haven't you burned the house to the ground figuratively speaking. What do you think your kids are going to think of you when they get older and understand the whole situation? If nothing else, you have an obligation towards your kids to show that such massive disrespect, humiliation, and shameful behaviour will never be tolerated.
I feel you and not wanting to jump off the cliff with your arms wide open. But trust in yourself that you will fall for a while, but will eventually glide and find your feet firmly on the ground. You cannot keep standing on the edge forever - just let go.
