@Ailuros,
While my situation is a little different to your situation (my parent's aren't divorced and therefore no "wicked witch" to speak of), I do know what it's like to have to cut ties with family. I haven't seen my father since sometime around 2013/2014, and don't have any interest in seeing him again either.
My father was almost never there when I was growing up, and was like a ghost that popped in for a visit when he was actually there for maybe 3 months of the year, or maybe 6 months of it, if I was lucky. He'd pretend like he had always been there, thinking that he could have the same relationship as someone who WAS actually there for at least most of the year. Looking back, I didn't even know who he was as a person, I really didn't. To cut a much longer story short; I moved out of home as soon as I could (I think around 17 or 18 years old from memory), as I just couldn't live there anymore and would likely be dead now if I'd stayed there any longer (no joke). So I basically didn't have any contact with anyone from my family for around 6 years after I moved out.
Then I made the mistake of reuniting with them, including my father. It was fine in the beginning, but when they realized I wasn't just going to do anything they told me to do and be the person
they wanted me to be, well, things weren't fine anymore. I also realized that my father hadn't changed one bit (yes, pretty stupid of me think there was any possibility of that happening in the first place, I admit), he was still a hypocritical, arrogant, racist heap of ****. This is why I just can't stand people who want to be hypocritical, racist and alike. As there IS a difference between just not being prefect (who is?), and willfully and knowingly being a racist, hypocritical piece of ****. And like the woman you speak of, around others, he'd act like a completely different person.
So while it's hard to have to cut ties with him for good AFAICS; I have to face facts, he is never going to change, and as others have noted above, I do have a choice as to what I can do. So the only viable option I can see, and as hard as it is to have to do, is to just cut him out of my life and move on. I wish I didn't have to, but the facts are I have two choices: 1) put up with a hypocritical, racist asshole, knowing that
isn't someone I want to be myself and how wrong it is. 2) cut him out of my life and move on. I've thought about those two choices many, many time over now, and the latter of the two is the one that always seems the best one, as difficult as it is.
So yeah, I understand how you feel, I really do. But particularly given what jespah and chai2 have said above, and what I was thinking anyway, it really has put things into focus for me (and thank you jespah and chai2 for that too
). So hopefully you can make a choice that you can live with, best of luck.