If my husband and i split, what should our living arrangement be?

who should have to move out? i realize that the house belongs to both of us, but i will have primary custody of our 3 children and to me it makes sense that we shouldn't uproot the kids from their home to move to a temporary home. his parents live less than two miles from us and they have a gigantic house with a fully finished basement including a kitchen/tv room/bathroom/and a private entry/exit so he can come and go as he pleases. i have zero family support, on the other hand. he thinks i should take our kids and find an apartment. i'm really not sure what i think is fair but i'm curious as to what you all think.