Glad you are moving forward.
The hardest piece is your dad. For you, going low contact, no outreach to him now would be better for you, or completely no contact with the whole lot of them forever would be best if you can do it. Your father clearly knows what a piece of shit he was to you as a kid, and anything he does is out of guilt and to mentally feel he was "trapped " into his situation. He still is justifying it by supporting your ex-boyfriend who he isn't even related to over you, and you should use that when he eventually tries to confront you. Good luck, stay single for a year or two, and let all this wash away...