I agree very much with Proudnscary.
I spent ten years trying to work around my MIL and her demands so I didn't rock the boat and upset anybody. Sometimes the strategies for dealing with her while trying to maintain our own lives while keeping her happy when her attention turned to us were like playing Grandmaster Chess.
And nothing was ever good enough unless it was exactly the way MIL wanted it and neither she nor FIL cared if they hurt anyone else's feelings or caused upset within the family. They expected everyone's lives to stop or be put on hold at a moments notice to suit them on a whim.
When MIL resorted to making intrusive and finally offensive comments about the babies we lost to stillbirth and prematurity I had to say enough was enough.
I took a big step back from them and limited my contact with them. Still went to visit them, still had them to visit us, but we set ground rules so it was on our terms and let them know without a doubt that any more comments about the babies would be the end.
It didn't work. Instead they set up a stalking campaign against me, they did the 17 calls in a short space of time demanding to know where we were or to speak to me, they would park outside the house when they knew DH was at work and stare at the windows, if they saw me in the street they would follow me slowly in their car. Once they drove onto the pavement to block my way and nearly hit DS in his pram. If we went to the shop we had to pass their house and if we didn't call in they would ring the whole family to say we were ignoring them.
They made up lie after lie after lie about me, to the point that I think they believe them now. They wound BIL up so much that he called me a "fucking evil mad bitch" accusing me of lying about the things they said about the babies and disowned DH as his brother. FIL also disowned DH, said some awful things about me and told DH they were finished with us forever. A few weeks later they were calling us names because we hadn't been to see them and denied ever having the conversation where they told DH they didn't want to see us anymore because we were users who thought we were too good for them.
Over the phone MIL called me a bitch and wished my DH had never met me. Then she lied to DH about what had happened and said I had just attacked her verbally out of the blue (I hadn't said a bad word to her, I'd just refused to accept that MIL was in charge now and I would have to do as I was told. This is what she was shouting at me prior to the bitch comment.)
They pushed me to the point of illness, I had panic attacks and felt scared to go out in case I met them accidentally. I still do worry. Every time I open the blinds or curtains I worry that their car will be parked outside the house. If I open the front door I worry that they will be walking down the path. If I go shopping I expect to see them or realise they are following me. When I leave DS at nursery I wonder if they are parked somewhere, watching us. We got caller display because of the phone calls.
That's how bad it was. DH grew up being told that his mother suffered from depression and would have a mental breakdown if he ever upset her or said no to her. He's spent his life not rocking the boat to keep her happy. She's had no treatment, she takes no medication. And the depression only comes on if she is not the centre of attention and getting her own way.
And I truly believe that if FIL or some other adult had done something to stop her when DH and his siblings were children we would all be better for it now, MIL and FIL included. FIL has told SIL that he can cope with everything but MIL's stubbornness and need to get her own way all the time, yet all hell breaks loose if someone else feels the same way.
MIL will ring up and weep, then FIL will ring up and shout, and that pattern goes on until the person they are trying to manipulate gives in and does whatever it is they want.
MIL will tell DH she loves me and wants to make up with me but then she tells the rest of the family that she hates me and blames me for everything.
If someone had stood up to her years ago and told her she needed to get help if she really is depressed then everyone would be better off now. Loyalty can only go so far before it turns into something that supports the destructive behaviour and alienates everyone else.
The OP says her DH's loyalty to his mother is helping to destroy their marriage. I know what she means because I have felt the same about my DH when he defends his mother.
When she looked at the photo of our beautiful but tiny premature daughter and asked me if "she was born with all of her face intact?" I wanted to kill her. DH did snap at her that she could see all of our daughters face but within no time at all he was passing off her comment as "just coming out wrong." Yet he can't explain what she really meant by it and neither can she.
I may still have been doing what we always did, biting our tongues, finding massive little compromises to keep them happy, changing plans to keep the peace and telling myself it didn't matter but the experience of losing two babies in a short space of time was just too horrific to cope with. It's not something you get over or accept in a short space of time and within three days of our son being stillborn the nasty comments and intrusive behaviour had started. But still, for two years more I tried to make allowances before I reached the point of not being able to do it anymore.
I spent ten years doing it your way ledkr and if you are happy then good on you. But Proudnscary's way is the one that has brought peace and sanity back into our lives (mostly, we still get the odd text or phone call but DH deals with them now).