Slapping you is entirely unacceptable, and placing a camera in the bedroom unbeknownst to you? Was he recording your sex? Why in the bedroom if he claims he wants to "watch over the family? " Seems he wanted instead to record your sex secretly? Either way, it's so wrong of him not to ask you first. Or to even tell you. Slapping you is physical abuse.

You say you love each other. Love does NOT involve hitting and it does NOT involve abuse.

And laughing at you is also emotional abuse when you're trying to tell him you miss him. That is not Ok either.

This is not a healthy relationship.

Can you leave? Stay with friends or family? I wouldn't put up with abuse. Not for one second.

Do you have your own therapist? It seems you need a professional's perspective.