To the OP, a word of advice:
The basis of the vast majority of interpersonal relationships is the advancing of personal interest. You get an advantage out of associating with someone, and vice versa. This is because humanity at large is greedy and self centered. When you cease being useful to someone, when your goals no longer align, then you are going to be dropped like a hot rock.
This happens even with people who are close to you. People have been betraying those close to them since the dawn of time, and it won't stop for you.
With regards to romantic relationships in specific, studies have shown that the availability of better alternatives is a better predictor of whether couples will break up than how highly they rate their love for one another, and economic status is a greater factor in the decision to divorce than how seriously people take marriage. This is again because most people are greedy and self centered, and will choose to advance their own self interests rather than remain loyal to something that is no longer profitable.
Just something to keep in mind as you grow up.