This is a horrible way to live but honestly there's no consequences for your WW so she has zero incentive to change. She's got the family at home for stability and an OM for fun/excitement/sex. She cares about only herself. All of her arguments with you are about her not being put ahead of everything else. OM is happy to put her first as long as she continues to open her legs. If she cut that off he'd drop her in a second.
As I've said before, you have zero chance of working on the marriage as long as there are more than 2 people in it. You have more than 2 people in yours. This unpleasant life you're living right now will continue as long as you allow it. The power to put a stop to it and find happiness is in your hands.
