I know we don’t talk much in person and it’s kind of an awkward situation whenever we’re together (at least it is for me), but I just want you to know that I have no problem with you. I think you’re a really nice girl and we actually have a lot in common. If it weren’t for the elephant in the room we could probably be good friends. I just want to set one thing straight: Yes, I do have a problem with you dating him, but not for the reason you probably think. It’s not that I want him back (I would need some serious brain damage before that happened), but that you’re making him happy and he doesn’t deserve it. And you definitely don’t deserve what’s going to happen the moment he feels like dating you is no longer convenient. I don’t want you to get hurt, but unless he’s changed drastically (and let’s face it- he probably hasn’t), you will.
If I ever told you any of this you’d just think I’m bitter and jealous, but honestly, I worry about you. Don’t let him hurt you like he hurt me. And for the love of God, stop making him so happy for no reason. Make him work for that shit.