Oh, I feel you. I think you are in a similar situation to us, and it took us a long time to find our 'happy place'.
For different reasons, both sides of our families are difficult. This one doesn't get along with that one, these ones drive us crazy, this person is controlling and demeaning, etc. We went through a period of a lot of anger, being so mad that everyone couldn't get along (including us). Then some sadness, this is not what I thought family would be like, this is not what I wanted.
But recently, I've come to a good place. I needed to focus on my husband and our daughter, and made everyone else a little less relevant in my life. I still love them all, and include them when possible for big events. But I expect nothing of them, and need nothing from them. I call a little less often, don't connect much on FB, and don't seek out times to get together. When we are together, my mindset is different and I keep everyone more at arm's length, you know?
I admit, the change is mostly in me, and in my head. Realizing that they can be a part of my life, but not how I thought, set me free. I don't really care what they think of me. I accept their shortcomings, and realize maybe I had something to do with this (not saying that applies to you).
It really is a happier existence now, and I hope it continues to be more comfortable to live this way. There's no anger, no resentment. I will admit, being sad over losing how I thought my extended family would be still creeps up sometimes, but I work through it. I'm happy this way overall. I hope you get to a good place, and realize as others said that the change will have to come from you. They are not going to change.
A break would be good for you- to gain a little perspective! Good luck and God bless!