Great advice from the previous posters. My current partner divorced after we'd been together over three years and we too faced the idea of us living together. We had wanted to for years -with his wife and daughter - but that didn't work out. It seemed important to me that he have some time between living with her and living with me (long story). I felt bad holding to this boundary but he did find a room to rent in a house with room for his dog and great people. We couldn't have lived in my place anyway and it turned out fine. Supporting him emotionally through the process - exactly as they said above.
Me: mono, 52, serving S in a PE relationship for six years, living together since April 2012
S: has been poly since he can remember, 37
A: His new girl, under consideration