My ex-wife lived with me for 3 months following our decision to get a divorce. The first month was hell, the rest was okay with moments of unpleasantness.
I gave up keeping my house as clean as I wanted it. She wasn’t as into keeping it clean as I was, and it got dreary trying to keep up with both of our messes. So I let her stuff pile up, kept small corners of cleanliness for myself, and held out until her house funding came through.
Most of her things are gone. I am amazed at how much joy I get from making a space my own. I haven’t done that in 4 years.