Hi Sunny,
Relationship means you try to satisfy the person you are gonna be friends with, and the same with that person, he should try to satisfy what u need.
Sex has got no values by itself. That's what animals do innately. It is valuable when friendship, sincerity, generousity and love is behind it.
The story is simple. If the relationship is only for sex, this relationship will have no values and you should try to get rid of it quickly. If the second, Sex is full of values and you should try to grow up ur relation more and more.