how to tell your parents you are moving to your boyfriends place?

I'm in college so I dont live with my parents anymore, but they seem to decide everything for me. My roomate is moving out, and since I'm already at my boyfriends place most of the time it is only logical to move out aswell and move in with him. When I proposed the idea to my parents they got angry to the point when they said if i do that i'm not allowed to come back home and then they decide to chose my next roomate without even asking me.

Both him and I discussed everything from financials to what happens if it doesnt work out. We are financially independent.

How do I tell them that this is what I decided and this is what i want to do without all hell breaking loose again?