Originally Posted by
Eauchiche 
Dear Norma
So sorry for what brings you here. My attempts to offer advice will be flawed here, so please take what you need and leave the rest.
1. The children come first. They deserve better than some crazy person in their home, blood relative or not.
2. I, like your husband, came to view some very sick family dynamics as "normal." It is all we knew growing up. That doesn't make it "normal."
3. Your husband was extremely fortunate to marry someone like you. This is a good place for him to heal from his childhood.
4. If he wants to see his Mom, encourage him to buy a ticket and GO SEE HER. Keep this woman out of your house and AWAY from your kids.
Thank you, Eauchiche, for your kind reply!
It felt good to hear it confirmed that keeping the crazy away from the child - who now is old enough to ask questions on the spot - is the priority. That is what made me see that we always have to be able to leave. I can still protect my child against the heartbreak my husband is still going through and that is my duty. Reading stories here from husbands, wives, and ACoAs has been so very helpful in understanding the futility of applying normal expectations to addicts, and I want to use others' hard-won experience as best as I can, since I can see my own is completely unhelpful.
My husband explicitly wants our child to meet his mother, so that they can start building a relationship. I suggested that we spend a few days longer in town for Christmas to spend with her instead (we don't stay with either bio in-law, we stay with my de facto inlaws who are his bio aunt and uncle), but he wasn't interested.
I don't think he realizes that it's incredibly likely that our limit-setting will trigger crazy behavior every time we see her, because it brings up deeply personal, hurtful baggage for her (being a bad mom/grandmother) that she only knows how to handle with some kind of mind deadener. I also don't think he realizes how quickly she will burn bridges with our child with the crazy, because unlike him, our child expects functioning. He just doesn't seem to realize she isn't capable of building a relationship with our child while she's in active addiction regardless of what we do or don't do, and that leaving all bridges unburned by not even trying to cross is the best shot at them having a relationship one day.
Is there any hope of having that discussion at this point? Or do I just have to take the heat and drama for banning her without a common understanding of the situation?