Ive been there man but you're still young, you'll find other women you share a connection with. And not rub salt in the wound but it's a good thing you realize this was your fault once you realize your own behavior is problematic you can work to change it, I would recommend you really reflect on yourself and the person you are and ask what else you'd want to change about yourself that is the only way you can grow as person and become the man that you're supposed to be. Pain is the best teacher and regret is a close second now let go of the anger and work on bettering yourself so you'll be ready for the next relationship you find yourself in. Last piece of advice let this girl go, no matter what your heart tells you leave her alone. If the future bring you guys back together than it'll have to be her decision trying to force it or wait out her relationship is only going to prevent you from moving on an finding your true happiniess