Haddaway may have asked it the best. It's been called a many splendored thing, a gift, a once in a lifetime adventure... And so on and so forth, but love is not that simple. And it's definitely not just a chemical reaction. As a kid, you think that you will meet the person that you fall in love with and run into a window, trip on a sidewalk,  or simply feel magic all about you.

No, finding love is a process. You become attracted to someone. You get to know one another and then you find one day that you look at one another in a different way. You don't want to be without them. You want to steal all of one another's time, and it is not work to be together. 

That is the most important thing, in my mind, is that after the afterglow of falling for one another, you remember that you still have a life separate from one another.  A relationship can only succeed if you are mutually symbiotic (Where you both benefit, and you still have friends and your own time). If a relationship becomes parasitic, then one of you is giving too much. Only you can decide what type of relationship that you are willing to have.