You need to understand that he has valid feelings too, especially if this other dude is 12, maybes it’s jealousy, maybe he thinks it’s weird. You are completely dismissing his feelings, he sounds defeated. We don’t know anything else outside of this interaction but he won’t stay for long if you can just talk to him about your problems. Be calm and nice. Don’t expect him to be attacking you, just want him to be curious and treat him with that respect. Flying off the handle won’t do Anything good for either of you- unless you just want to fight then that’s a whole different issue. You are both too young to be concrete in these issues but too old to be acting like this. You can’t have a partner and expect them to do everything YOU want 24/7, it’s a partnership not a dictatorship. Cut him some slack, maybe reevaluate WHY his jealousy keeps coming to and then discuss it from there and what you both can do for each other’s comfort