I think GGP actually addresses that via: > what is generally left is (sometimes hopefully) a caring, appreciation, and high regard for the object of "love". Y

I think GGP actually addresses that via: > what is generally left is (sometimes hopefully) a caring, appreciation, and high regard for the object of "love". You still value the shared responsibility you have for your partner high enough that you have developed platonic love to a certain degree, ie. you can't imagine finding someone else to build up the same amount of caring/appreciation/shared life experiences with, even if the romantic love between the couple is at a low point. Even if one partner grows attracted to another person, that is only the romantic / eros love that brought the initial couple together, while that platonic love still exists and would take a lot longer to build up with the new romantic partner, should they choose to give up all the progress they've already made and re-marry.