I really hate confrontation too, I don't speak my mind to them at all really! For us it helps that MIL often texts or emails us both and the I hassle DH to reply. I say to him directly: you need to reply so I don't have to.
You can't change them. An email to them or a confrontation will only set off a chain reaction of toxic behaviour.
All you can change is how you (and DH as a team) deal with them.
I was the same as you, I took the brunt of it and I became very sad and very frustrated. I then walked a long road to get DH to support me but it worked in the end. I trust him a lot more on this topic now.
I told him how badly it affected me and that to tell me to just ignore it was wishful thinking.
I explained it like a triangle: her behaviour is bad. Seeing them can make me angry(corner 1, though I don't really 'do' angry) or sad (corner 2). Or we have to see her less (corner 3).
I also go back to this first principle when I start thinking about changing her behaviour. But I can't. A great conversation with a psychologist friend helped me see that.
We're then left with the triangle ans seeing them directly causes me pain. As simple as that.
Could you try to talk to your DH?