Most Helpful Guy
If he treated you like that. You need to let him go, it makes no difference if he's dating someone else or just got someone else. Of course it will hurt that means you have a special place for him in your heart during that time. Like the girls said below... find your girlfriends go out, see a movie, sit in the tub, get some Chamamile tea (my favorite) and just be content that there is nothing else important aside from what you're doing at the present moment. Only thing to do is let time do its work sucks to hear but its true. You are still loved by others.
Most Helpful Girl
You just have to try and not focus on it, it really sucks seeing someone you love with someone else but you just have to be strong. Go out with your girlfriends or have a nice bubble bath and read and take your mind off things. It's hard but you'll get over it eventually. *hugs*