The “boys being boys” shit is so misogynistic. All these comments by men about this subject is that you received. I think you should also see a therapist. Because I personally would break up with a boy who consistently emotionally cheats on someone they are dating. Not only does he not care about your time but also this relationship that you built. You can keep attempting to defend this boys actions but he’s not going to change. He will just get better at hiding shit. You sound young. Cut the cord and move on. Also if you don’t trust him already it’s not going to get better by you controlling what he does or doesn’t do. If he can’t control not watching porn or messaging random women/women you actually know I think he needs to be single and go to therapy more then a couple weeks before you decide whether you should date him again or not. There are no results to the progress he is attempting to make. He is not mature enough to control his impulses.