So my wife found out Friday that her sister's husband has been cheating on her. they were married in October 2011 and the affair started in july 2012. at first he told her it only happend once and that the woman "seduced" him and threw herself at him. Fine. An ooops I can forgive, but as it went on, it turned into a 5 month affair having sex dozens of times. So at this point, i'm mad, I'm staying out of, letting them work it out. They are 22 are 24 years old. I'm not perfect, I'm not going to be smug and act like a saint. But last night before bed I blew my stack. Her sister called and said they got more into it and he admitted to her that when he told his parents about it, his father said he didn't blame him for doing it because my sister in law is controlling and bossy. Then.... and this is what has me posting here... and trying NOT to just go beat the fuck out of this ignorant white trash bumkin.... he told her the reason he cheated is because she is never on top during sex and won't do anal. I didn't sleep last night. I think of this girl as a little sister and I just want to get my hands around this idiots throat. Talk me down.