With the new information you've given us, all I can add is: Counseling. Therapy.
For all three of you, both as a group and individually. You need professional help, and in my opinion are beyond the scope of this forum to help you. To move past your upbringing, learn healthy coping skills, learn healthy relationship skills, etc will take regular, ongoing work for quite some time, as I see it. Maybe even years. If you want to be with these people, in a healthy environment that doesn't damage the children being brought into this drama, then you have to start doing serious work, beyond a website of strangers.
Pan Female, Hinge in a V between my mono (straight) husband, Monochrome and my poly (pan) partner, ThatGuyInBlack