You have a right to be annoyed, but exercising that right is only going to hurt you. People like him aren't losing any sleep, so I suggest you just move on. At the very least you found out he is not a good guy early on. Would have been far worse to develop feelings for him and then find out. In a way, you should thank him for being so spectacularly bad, because if he was just a bit better, he would have strung you on for a while and then hurt you. I would see this like a tree branch falling and almost hitting you, but not actually. Consider yourself fortunate it wasn't worse, and put your energy into living your life fully.