Different people can have different goals / purposes for the same institution.

Marriage is one example.

Another that comes to mind is going to college. Some see it as a chance to discover themselves, others see it as essentially a training program for specific careers.

From your profile, I'm guessing you approach this from a Judeo-Christian perspective? If you believe the institution of marriage is defined and ordained by God, then your normative view of it makes sense. Just be aware that not everyone in this discussion will share those assumptions.

> From your profile, I'm guessing you approach this from a Judeo-Christian perspective?

Perhaps they are someone stuck in a bad marriage but trying to justify it... Who knows?