I am sorry for your struggles.

But I probably have a different take on this. I believe if a couple want to play house, they need to become self supporting and have their own place. I wouldn't allow my daughter to move her boyfriend into my house.

I think if people aren't ready to fully support themselves they shouldn't bring their date to live with them and their parents. They could date and have boyfriend over for dinner but not play house.

Overall couples living with their parents smells trouble. It rarely ends well. By living with your parents you telling them you are still a child yet you want to be treated as an adult. It rarely works out.

The other concern I have is 8 year-engagement. Are you not ready for marriage? 8 years is long time.
I am sorry you have difficult parents, I can relate. But by continue living with them and bringing your partners thee doesn't help the situation