bjl, welcome to Psych Central.

I am so sorry you met someone you fell in love with and it did not work out into a life commitment for you. It sounds to me like this young woman simply was not ready to invest in a commitment. Unfortunately, that can happen and it sure can be hard on the one that feels that person is the "one" that they would like to have a long committed relationship with.
You deserve to grieve this, but keep in mind that you learned some things from this individual, even though it was not a long term relationship. Each person we meet is going to be another person we learn from. You did learn you can have strong feelings, and you learned you want to have that. There "are" other women that are looking for relationships out there, "nice" women too. Give yourself a chance to find another woman and one that is ready for a relationship that can become more of a commitment.