live under the same roof
To share a house together (with someone). At one point, my parents, my adult children, their kids, Terry, and myself were all living under the same roof—it was mayhem! I'm leaving, Tom. I refuse to live under the same roof as a criminal. As long as you live under the same roof with us, you will follow our rules.
live under the same roof (with someone)
Fig. to share a dwelling with someone. (Implies living in a close relationships, as a husband and wife.) I don't think I can go on living under the same roof with her. She was quite happy to live under the same roof with him.