Statesboro, GA, USA
I must agree with the main of what has been said. It takes much more than an emotional attachment to sustain a lifelong commitment of love. I won't say that this is unimportant or "just chemical", but it is not the most important part. I see the emotional high of falling in love much like the ignition starter of a car. You can't get the car going without it (in some form or another), but it will never keep the car rolling by itself.
I like the different words the Greeks had for "love" describing it's different attributes. Eros was that steamy passionate, blinding, emotion-flooded kind of love. Phileo was the love that was more like "brotherly" love, or a deep friendship. Agape was a love that desired the absolute good of another unconditionally.
I know the American concept of love is usually very shallow, patterned mainly after the "eros" definition. It's easy to see that on television, in the movies, etc...that kind of love is elevated beyond it's proper place. If the other "deeper" types of love do not come in and take root in a relationship, the feelings will die away and there will be nothing left to hold things together. If the deeper loves are there, feelings may wither at times, but the root system holds (and promises that feelings will come back much like the flower of a plant). Friendship, and unconditional love (which is an act of the will) holds love together through the winter seasons of life when feelings flag.
Another interesting thing is that the other dimensions of love (phileo, and agape) are not so "me-ish" as eros is. Case in point, when is the last time you had an agonizing crush on someone and truly considered the other person's feelings above your own? Whenever I had those in the past, it didn't seem to matter until my aspirations were shot down to the pits of rejection. LOL.