When dealing with a loss of a relationship such as that (same with even a friend) you have to remember that it is all part of God's plan. If it was in his will for the two of you to end up together, then that's what it would/will be. However, if that is not what he has in store for you, then don't linger on it. Look forward to see what he has planned for you.
I went through a similar situation not too long ago, and at the end of our relationship I was heartbroken and felt lost.
I seeked a stronger relationship with Christ afterwards, and it helped me to realize that I needed to build myself. If it was that easy for some one to knock me down, I wasn't ready for that in the first place. Find purpose from the Lord, strengthen your faith, and remember to take each event of life and turn it into a lesson so that you may better yourself from it.
God bless you