" they are without fault before the throne of God" (Rev. 14:5)
I know I have looked up at the Lord and told Him I was HIS completely. I believe scripture says God answers such heart-cry, "I have betrothed thee to Me forever." Something tells me GOD's eternal love bond, forged by God between Himself and one of his own, can never be broken, not by cruelty, not by infidelity, not by man-made pressuring of relationships, not by divorce.
BECAUSE WE ARE MARRIED IN HIM, it can be said we "have to stay married", but the argument is never "Christians stay married to each other"; but "They stay One In CHRIST". It might sound the same but is actually different, and when that is understood, variables become easier to see.
Anything else MUST start from there: how it affects CHRIST.
It's a little like getting a handle on the book of Revelation, isn't it? Christ has to be kept the focal point, or everything can get pretty chaotic-scary. We just need to focus on the Lamb and pray God will show us one step at a time what He wants us to see.