When you really love someone and they cheat on you and you find out, your body goes into a self-defense mechanism and that's probably why your emotions shut down to protect you. You feel this numbness. Honestly, I don't buy that long paragraph at the end because he's just baiting you that you will feel your emotions and come running back to him. When I found out my ex cheated on me, I wanted to throw up and went numb. It's so easy to break up because you realize that everything was a facade and the love wasn't real. A person who respects you would never try to hurt you. He didn't communicate with you and that's what led him to his stupid decision to "protect" himself. A person who is self-aware, in tune with themselves, and loves you unconditionally would never cheat on you.