I see so much of me in your posts. I remember how angry I was that anyone was ok with my ex and OW. I felt like I was being betrayed and they were "OKing" the affair. I was close with my SIL and it hurt when she was accepting.
But really, this is family. They are going to love and support their family members no matter what. They are not going to reject the people they love because of his poor choices, especially when it doesn't directly affect them. I learned this the hard way when I realized how exhausting it was to be mad at everyone who would spend time with them. And I realized how unrealistic it was to expect them not to.
It's his family and you cannot take it personally because you feel like they aren't rejecting him or OW. That actually has nothing to do with you. It's unfair to them to expect them to write off their family.
I hope one day you come to some peace soon. because if it's going to ruin your day and upset you and anger you when their family accepts them, then you are going to be upset more often than not. You owe it to yourself not to let it affect your life so much.
