Breaking and entering if no SA?

I don’t yet have a separation agreement and I live in what was the marital home. I’ve not yet changed the locks but another post on this forum has me a concerned. It sounds like he could just move back in. If I change the locks could I call the police if he were to break in, even without an agreement in place? In other words, does changing the locks truly protect me or is the agreement that really does it?

Once a party leave the home, they cannot return absent express invitation. There is a law in effect which classifies the behavior as domestic criminal trespass. Some police officers are unfamiliar with this law, so I always recommend the locks be changed soon after one party leaves.