Stephen Collins and Faye Grant -- Who's Been Sleeping in My Bed?

Stephen Collins and Faye Grant had a bizarre living arrangement, with NO designated bedrooms for them and their daughter ... this according to new legal docs.

Grant filed the docs -- obtained by TMZ -- in her divorce case, explaining they have 3 houses on 2 adjoining lots in Brentwood, CA.

Grant says, "Stephen, our daughter and I did not have designated bedrooms in any one house: we would frequently rotate and move around to different bedrooms in the different houses."

The houses came up because Grant wants the home sold and the proceeds divided. As we previously reported, she doesn't want any future financial involvement with Collins in case he's sued by one of the women with whom he had improper sexual contact.