The hardest time in my life was a lot like yours. Divorcing the ex and the FOO taking his side. They didn't take his side because I did anything wrong, but as the SG, I am always in the wrong and they've always been disloyal to their children in times of crisis.
They called me after that all started, while breezily on vacation in Alaska. "Could you accept a shipment of a few hundred pounds of halibut and have it frozen for us?"
My answer: No (I was tired of being at their beck and call and here I'm emotionally bankrupt from my stbex and they are needing me more and more.)
I said: Why don't you call my sister, I have my hands full right now.
Since then, they called my sister, that was all 17 years ago now, and even last month my mom was shoving in my face that 'sister is much better than I am'......ah, thank you very much that's another reason I see no reason to call and talk to you.
So anyways, friends are God's apology for family. You'll need your friends around you right now. It's okay to need friends. And yeah, it sucks to have lousy family.