Dearheart, I know this hurts and hurts badly. But think about it -- you met him when you were 18. You were very young. You have MANY MANY years ahead of you! This guy is NOT worth your life! NO man is worth any woman's life! Don't every let any man carry that much worth to you! If you do, you will certainly be disappointed and hurt.
Naturally because he was your first, you'll always carry some piece of him in your heart, but don't close your heart to everyone else! You WILL find someone else to love -- and probably love even more than THIS one! Like I said, you were very young, and young love is immature love. When you've grown up, "adult love" goes deeper as it takes into account the commitment, the responsibilities, and all that goes with being a couple/getting married, etc.
If you're having too much trouble getting over this, talk with a therapist. He can help you get thru this, and deal with the pain. Perhaps even a grief counseling could help. You can contact one thru Hospice. They'll be happy to talk with you, as a breakup is much like a death, in that it's the death of a relationship. So give them a call. I wish you the very best. Please take care. Hugs, Lee