How do you set boundaries with a narcissistic mother in law?

You know that saying, “treat your daughter in law right and you’ll gain a daughter. Treat her wrong and you’ll lose a son” ?

This doesn’t apply with my marriage. My husband is a mommy’s boy. Sometimes I think it has a lot to do with her narcissistic ways. Maybe it’s her mind games?

Who knows.

I tried setting boundaries. I said, “tried” because it seems like I failed!

My sister in law (her daughter in law) and son was at my precious mother in laws house. My (4) year old son did something she didn’t like (jumped in the living room) and she grabbed the belt and spanked him!

My sister in law was speechless. She told me immediately after it happened!

I told my husband and he told his mom that I was angry about her abusing my son. (I say abuse because I heard horror stories of how she use to beat her sons— one time she grabbed a wooden spoon and hit the back of her sons neck real hard— one of my brother in laws said.. she has done more!🥺😢)

She went on to say, “I’m very angry! WHAT, I can’t even hit and discipline my own grandson! He’s my grandson!”

I feel like she is trying to pass on generational curses down my family and I don’t want this to happen. How do I make my husband see that this is in fact not normal?

She is so toxic. I would honestly love to go non contact and cut her out completely, but my husband is a mommy’s boy 😩🫠