It's hard for me to know what is going on in his head so here goes one of many possibilities.
In his heart he knows that intercourse is more than just a physical thing... there is a spirtual component so he is torn between two things... his love for you and his love for God.
No guarantees, but the best possibility is the following:
1) Consider letting Jesus come into your life and follow Him making adjustment in your lifestyle as you grow in understanding,
2) As you grow follow Jesus, by waiting for the spirital union of intimacy for after you are married
3) By growing and honoring God, this young man will then be able to love God by waiting for intimacy and still love you by getting married at the right time.
4) Get to know him from mind to mind because that is what makes a marriage work.
Just a shot in the dark (so to speak).
this is a very short version