Don't think like that. You should be angry not defeated. She cheated on you while you were married and had children together. Thats one of the largest betrayals of trust you can have. Don't let her get a single scrap more than what she gets when you go to a lawyer and stand up for yourself. Fuck that woman and I'd say the same thing if it was the man cheating on his wife. Fuck anybody who would throw away that kind of history so they could screw somebody else.