If he is not taking therapy seriously try mediation services a paint of neutral third parties will hear both your sides and then try to get him to hear and understand how and why his actions are violating your trust and relationship and will broker a contract between the two of you ,this way it is in writting and someone else is aware of his behaviour, it establishes a paper trail to protect you , I have been a mediator and victim advocate in the court system for 30 years ,this is not normal or healthy ,but I have seen it before and seen it both work and not work ,in your situation I don't have a crystal ball ,however getting someone else involved very often gets the point across that he is out of bounds ,and is jeopardizing the family , the one he claims to be wanting to endure is safe . He needs to understand his actions are having the opposite effect on you .

And I am sorry to say you both need to stop resorting to violence to try and get your point heard ,violence never works especialy in a domestic relationship , eventually it will escalate from slaps to something worse ,you can't hunting that bell ,however you can admit neither of you should have done it in the past or future .

Always let calmer heads prevail ,if he doesn't get your point or vice versa walk away and try again later .