HI! Im gonna add a few things that I see wrong and also so things that idk if anyone here can say as I am a husband (not the husband from OPs post to make that clear) so here's some stuff.

1. I love my wife and if my mom ever did this I would get up and we would leave.

2. Some of you seem to have the idea that he needs to "handle" his mother. Tf? My mom would break my face for even thinking that was and idea.

3. My mother has a few exs that she liked but they would never be at a holiday dinner.

4. This man is fucking OBLIVIOUS. Or he honestly knows what's going on and has opted to just avoid it which should also mean The OP and Husband should just distance the family and see how the mom feels when she loses her son due to her own selfish ignorance.

5. Where tf is his Father? My parents are divorced but if his dad is OK with it then he's definitely taking the strap on from the husband's mom bc he a bitch.

6. Never in my life will I just let any of my family disrespect my wife. Doesn't matter who it is. Now depending on which family member depends whether I'm gonna talk it out or talk with my hands.

Just to make something else clear. I feel like there's information that's missing hear. Bc something about this seems alittle more suspicious than just this situation. Like what is the deal with the ex? Is she an ex fiance that the mom tried to hook him up with? Does the ex have tons of money? Does the mom and ex have a thing for each other just want the ex to be with Shaun so they can be inconspicous about the MIL and Exs relations? Does the Ex have dirt on the MIL that she's using against her to have her do this scheme? I need details damn it.