Most Helpful Guy
After a while you will be able to live with the hurt and pain.
Most Helpful Girl
Time and keeping yourself distracted are the only things that'll really help, especially with your first 'real' heartbreak. Try to not look at it as that though. Not a heartbreak but a learning experience.
I know him being your first to have sex with makes it harder as well. However, you in reality lost nothing to him. Nothing more than the memory that he was your first. Do know that there'll be more guys you have sex with later in the future, so this will lose it's significance in comparison. I say that having lost my first 'serious' boyfriend as well as first guy I had sex with by him cheating on him a week after we had sex. I was a shell of my former self for over a year after that.
It'll get better. :)