I too come from a similar family, and yeah, that's way messed up.
Catch this - my brother was the best man when my WXH married his AP. So you know what? I can pick who I associate with, and it's not my brother.
I've always had to accommodate my family, until I moved away and stopped doing so. And while my mother bitched and moaned about the fact that I had moved so far away, I did just fine and was actually happier with a more emotionally distant relationship.
After my dad died, I ended up moving my mother down here to take care of her, but I do not have a close emotional relationship with her. I don't go to her for any type of emotional support or advice. I don't give a rat's ass of what she thinks of the men that I date. She seems to like the biggest assholes the most. Whatever, Mom.
It is not normal. Sadly, it's fairly common. It is not acceptable.
The good news is, you can tell your family that you've decided that they cannot treat you with such disrespect, so you're going to distance yourselves from them. They're going to tell you that you're insecure and blah blah blah all of their dysfunctional shit on you, but you don't have to listen to it. Or you can, and just tell them that you're sorry that they feel that way, but for your own mental health, you need to distance yourself from them.
Or better yet, don't say a damn thing and just do it.
The good news is, then you can go out and build your own family of supportive friends that don't pull those kind of stunts. I did it, and my God, they are so much more fun than my family of origin! The holidays are great now! They're small (not that my family was huge), and not stressful at all, and I actually look forward to get-togethers and celebrations now.
It's odd, but once I saw my family more objectively, it was easier to accept them as they are and control how I responded to their dysfunctionality. At one point, I would have thought that distancing from them would have been like cutting out my liver - just not possible if I expected to live. Now it seems like a perfectly reasonable thing to do.