@Scorpio8 the problem is if she was abusive - and obviously you haven't gone into specifics here, then your dad watched and let it happen. He may have stuck up for you kids but if she was abusive to any child and didnt immediately get up and run with those kids, he kind condoned that behaviour. I don't doubt you are lovely but having one favourite aka golden child, is so damaging to the others and puts the golden child under a lot of pressure to stay golden. I suspect this may be contributing to your anxiety (reading between the lines)
The cruise and holiday well again, if he earns he's own money he could have separately saved for a holiday back home if he so wished. The fact he chose not to (cannot be pinned her her solely) although as he's your dad probably easier for him than to take ownership of that.
The beaten husband is a worn out sad tale on how to let men get away with everything and blame the wives because it's convenient and I don't doubt he probably did this with your mother too. Now I'm not saying this to slate your dad, I'm saying that parents are human, biologically you love your parents no matter what. You may have been able to over look some of your sms qualities had she been your mum, and likely via versa. Part of becoming a adult is realising your parents aren't gods that can do wrong and although that maybe be a painful realisation it's a important one.
You want the situation to change, that means you have to acknowledge on some level he was complicit if not took a leading role in some of the things you hate your sm about. Because he could have made different choices but he didn't. And I suspect you posted because your really stuck, and you want to be unstuck.
My advice would be care less. Don't get into fights, get anxious over her saying zxy let it be water of a ducks back. Don't needle and try to convince your dad to leave her or wait around to tell her some home truths. It's to much emotional energy that doesn't need to be spent iMO. You may find that deescalating the emotions will help both of you rub along. I'm not saying you will be pals but it should be easier if there's less agg for every one.
Your pregnancy is your own, it's absolutely diddle shit to do with her on any level (btw kids can love the idea of baby brother or sister until they come along) while the adjustment happens, so if Dc does kick off suddenly post baby, it may not be her influence (I speak from experience here).
I totally get pregnancy related anxiety it suck arse. Hang on in there is my advice.
Also I know you may think she's jealous but I really do have to say, it maybe that she thinks of you very little tbh. And if that's the case and you dislike her, I can only class that as a win.