When the OW is his mother

[MrBond]

Dumped,

First of all, you should keep one thread. It helps to others can find you easier.

Second, your MIL cannot "convince" your H to dump you. In the end it is HIS decision. If HE chooses to be influenced by his parents, then that's his choice.

Don't fight against the current because it's going to end up being a losing battle. As hard as it is, don't feed into his ego or what he believes right now. As much as you can, step aside and give him space. Don't let his actions bother you if possible. No matter what you do or say, he will do and say the exact opposite just because you said it first.

As much as you can, keep the interactions short with just 'yes', 'no' and 'hmmm I'm sorry you feel that way" and then walk away. He can't argue with you if you don't argue back. Just walk away. You can do it.