Me and my boyfriend are 15 years old. We have been dating for about 2 months, and before we were official we have known each other for about 4 months. We both feel in love with each other after we first kissed. My boyfriend has been in relationships before but he told me he has never loved anyone in a relationship, just "liked" them. He tells me that he thought he is too young to fall in love, but that he is in love with me. I can believe him because he tells me he is "legit in love with me" and that it is serious love. He tells me that he cares for me, and will never pressure me into anything like sexual things. The farthest we have gone is hand job and fingering, only because we are so comfortable with each other and we felt right doing it. He treats me so well and I love him so much. He calls me beautiful instead of hot. He is so sweet to me and says the nicest things.

I know he loves me so much and he tells me he wants to be with me for a very long time, he says he wishes I could be forever. We have gotten into a discussion of sex one time, and we both agreed that we will not have sex until we wait a very long time.

Is the key to a long lasting teen relationship sex?
If we were together a long time, lets say about 8 months to a year, and we decided to have sex, would the relationship grow stronger, or would we move on?

I get a little worried worrying about this because I want a long happy relationship and have it not be all about sex.
I know teenage guys are out to get sex, that that's just what they want. But does it depend on the teen guy? Can some teens guys be in a long relationship or do they need more than one girl?

And me and my boyfriend are so happy together and we are so comfortable with each other and we can tell each other everything, and we can act however we want around each other. He always tells me he never wants to lose me, and he won't because I never want to lose him.

How can we have a long happy relationship? Is the key to a long happy relationship in teens just sex?
Please help, thanks