What IS good, and how do we determine it?

[abaris]

You are correct. If 2 people enter a relationship where they have promised each other to be committed for life, then the same applies.

Again, there's no religious safety belt attached. Also the promise, though given with honest intent, may become void at some time. I've seen people living out their years together although they never promised each other anything and weren't the least bit religious. I've also seen church marriages break apart after a few years and I've seen people making each others lives a living hell, but staying together since they believed in that binding religious contract.

There's never any guarantee when two people get together. They may have made the right or the wrong choice. People do change and it's always up to the individuals if they can and want to deal with these changes in their partners.