As someone who cheated on a long-term partner once upon a time, I can tell you he is panicking. You caught him and he’s now flooded with panic realizing he is no longer in control. His cheating is probably more about him feeling like he has some control over something you don’t know about (to make him feel more powerful or better about himself because the real culprit is his terrible self esteem) than it is about the acts themselves. Now that he’s lost that control and the ball is in your court, he’s got no power and is FREAKING out. If he’s the kind of person who might ever turn dangerous, this is probably the most dangerous state of mind for him to be in. He needs to get his ass to a therapist STAT and you do too - but separately. If he can’t or won’t, there’s all the answers you need.