You have a great boyfriend you get on with his family. Move away, start a new life.

My mother lived 5 minutes away but visited me twice in 7 years. She visited my sister, her favorite child twice a week.
That used to hurt.
If I visited her she would chat to me, but, if her 'favorite' daughter happened to walk through the door she'd forget me Totally. I'd disappear. If I tried to speak no one heard me. I was ignored, I was invisible.
If favorite child, mothers 'golden child' did speak to me it was in a sarcastic, patronizing tone, like she was talking to a rather pathetic idiot.

I spent 40 years yearning for a 'normal' mother. 40 wasted years.
Then I gave up on her, I wish I'd seen the light years earlier. its hard, I did grieve, cried for a long time. Cried for a mother I'd never had, cried for the mother she should have been.

Once I'd truly accepted the situation I felt better because I no longer yearned or waited for her, there was no point. This will sound harsh, for me the woman was dead.

Don't waste your life your energy on these toxic people.