We do have agreements based upon our joint responsibilities (kids, household, pets etc) about how much time any of us spends AWAY.
But there is no limit on partners coming over.
So for example; if my husband wanted to leave-he's limited to being gone 2 nights a week. But if his girlfriend wanted to come over, she could come over any time.
Thus-they could see each others 7 days a week. But only 2 of them away.
When all of the kids are grown-these things may change.
BUT They aren't rules I put on him or he put on me. They are expectations we have for ourselves regarding our current responsibilities.
"Love As Thou Wilt"