In the TV show Six Feet Under one of the couples found happiness when they realized they shouldn't live together but they were happy to date each other and see each other regularly, just not all the time, because the boyfriend went through cycles when he enjoyed socializing and cycles when he wanted to be alone.

That strikes me as fine if both people are happy with the arrangement, but if kids are in the picture or one of the partners is unhappy with this arrangement I don't know if it will work.