Hi Yaffle
It's good to hear from you, and it sounds like you are making some progress with keeping your own boundaries. I also hope your Dad is feeling better, and it is awesome that you have parents who love to watch your kids that live close by!
My parents (also getting more frail) love our two boys, but they live 3000 miles away - not so good for a quick break. I also get a fair bit of criticism for what and how I manage with my sons when I am with them on a solo weekend or so forth. It really does hurt to be criticized and held to a double standard - completely understand how you might feel angry and undermined.
The thing that really helped me get past being hurt was someone on this site asking me what would happen if I just did what I thought was best or what I wanted to do with my sons without engaging my wife. That has worked out a lot better for both of us. I don't ask questions, seek consent or really care what she says or thinks about what I choose to do with the kids. I know that I am a good dad, that I love my sons, support them and encourage them. When my uBPDw attacks me for something I am doing with the kids, I validate that she is upset, tell her I don't agree and keep on going with what I am doing.
Last night, my S9, S3 and I were making fruit kebobs for his class to celebrate S9's birthday. We didn't have enough skewers, wife was dysregulating throughout the evening and was tired, so I took the boys to the store (5 minutes from the house) to pick up some skewers. My wife came downstairs and began grilling me on why I'd take the kids out after dinner on a school night and why not just make fruit salad. Well, my S9 already had his school birthday celebration on Monday forgotten by everyone (except for me who was never told about it), had this idea of what
he wanted to do for the snack. But I didn't JADE any of it. I simply said we were all going and would be right back. The kids and I had a great time making the kebobs - made an assembly line of fruit to put on the skewers. Everyone had a job to do. They felt empowered. I felt empowered. I think that's the gist of it. The more you empower yourself as a dad, as a person, the better off you will be, and oddly, it may help your wife too.
Let us know if you find any success in trying a new approach. And again, it sure sounds like you are finding your way through better and better.