Congratulations on your upcoming marriage!

How did your mother end up living with you? You say your father agreed to it, so does that mean you did not have an equal say in this?

I ask because I am concerned about a possible repeat as you continue to serve as your father's caretaker.

I don't think you're selfish for wanting more space from your mother. I say, enjoy the fact she's moving out. I don't think severing ties completely would necessarily be in your best interest because it burdens you with having to avoid her for the rest of her life, but limiting your time with her sounds like a good idea to me.