To consider divorce because of MIL?

Just tell her straight no sugar coating it exactly how you feel. I have done it when Ive needed to and it had the desired effect they usually get the message. It might ruin your relationship for ever but hey you aren't exactly friends now so go for it otherwise it will fester and eat you up inside making you continually unhappy.

It all depends on what she is doing and how much (if any) support he is giving you

Let him take baby to visit MIL you step back and have some time to yourself and feet up, maybe until you are ready to see if you want her in your life again. I’m sure we would all be divorced if we divorced because of our MIL at some point or another especially after a new baby !!!

If your husband is ok, can’t you just “divorce” the mil? It’s his mum so you can’t tell him to stop speaking to her. But child visits at her house only, you don’t see her etc

YABU to divorce your DH because of your MIL. But YANBU to divorce him if he doesn't back you up over whatever stress she is causing you. What is she doing to upset you so much?

What exactly is she doing?

Have you spoken to him about it? Why not have him visit her at her house and limit her visits to your house? If she calls unannounced and Dh isn't there just don't answer the door, or open an upstairs window and tell her you and baby are in bed so it's not convenient. If she happens to have a key to your house and lets herself in, change the lock. What is it that she is doing to make you so anxious?

Clearly divorce is not the answer. You will never get this time back with your baby- your husband needs to take a firm stand against his mother. Completely reasonable to have very boundaried, limited contact, or if it comes to it, no contact just now.