Mary’s past and it’s relation to her abandonment issues

I am currently watching the latest episode of SLC and I am a bit confused. I was under the impression that Mary was cut off from her family because she got into a relationship with her stepgrandfather and they didn’t approve of that (also because she wanted the family church, which seemed like before if she didn’t marry rob sr, it would’ve went to her mom). Why does she feel abandoned by her family if she’s the one who schemed? I also saw a few comments talking about how she was essentially sold off by her family. I thought she consensually entered the marriage with Robert senior, leaving her previous husband for him. Basically, does anyone know the true story behind Mary and her family?

Also side note: the entire scene with Angie and Mary was so disturbing, i’m surprised people thought it was heart wrenching!!