Get a job, move out of your house, support yourself...send a card at the holidays. Send them extra money...drop by to clean the gutters and cut the lawn (and then leave).
You'll find your parents (especially your mom) will mellow out a lot after that.
The issue is you...you're cramping their lifestyle and they want you gone. Your mom didn't decide to spend the rest of her life with two guys...she picked your dad. You're the +1 in that house.
They've put up with your presence for 18yrs...that's enough for anyone.
They even started a new life in another country to give you a better chance to move out...and you're still there. Take the hint.
Just kidding....do what your mom says...she's your mom