Could need for each other (for eg to raise the children) masquerade the fact that there is little or no love for each other?
A real marriage or a partnership is based upon many, many things. It's normal and natural for some aspects to dominate while others occasionally take a back burner.
@Bolabi It would depend upon how adaptable one is, how communicative, and how seriously one takes the promises one makes. People do change for a lot of reasons, health being a big one. Sometimes staying in a relationship is damn hard, and eventually becomes impossible. Level of commitment to this end will vary from one person to the next, but there is never a guarantee on love.. It's a pity we can't foretell the future and save ourselves or potential partners a world of heartache.
I learned my parents , "stayed together for the kids ," for 25 years . I wish they had separated . They weren't happy . They weren't making anyone else happy . I do understand finances were a potent concern . Life was tough , even when working together to raise the family .