Is this a "primary' relationship because youve agreed that you will share primary style entanglemrnts like a home, kids and finances?
Anyway, I always believe that one has to trust their partner. That means trusting they wont let anyone else harm your relationship. Setting rules about who, how and when they spend time with someone doesn't allow them to prove that they can handle their relationships and responsibilities ethically. Often, they'll fail when pressured to do things someone else's way. If they're unable to handle things, as much as it sucks, it probably means you'd be better off apart. They might want to learn to do things differently to keep you or they might decide their lifestyle makes them happier than your relationship does.