Most Helpful Guy
Leave him. My gosh, you're exposing yourself to so much danger. The fact that he has literally decided that cheating deserves being literally killed, means that he has a killer instinct for those who cheat on him. He has a criminal and vigilante attitude. This idea or mentality, like a seed, can grow in the heart/mind and cause him to resort to violence or mental cruelty over disagreements or him not getting what he wants.
Plus, what if one day he begins to think that you are cheating, whereas you're not. He is going to do something dangerous and reckless and you can't do anything about it because he's probably made his move.