[NOTE: I wanted to change the normal post time today, to have this post at 11:11AM on 11/11/11 - but old habits die hard, so I changed it to 12:11AM where I live instead as a compromise. However, it was 11:11 in Utah when this posted. Just sayin'.]
Now, back to our regularly scheduled programming:
I personally believe that the core, fundamental, highest command relative to marriage ever given was to "cleave unto her and none else". In our terms, it is to become one as a couple in all ways. Frankly, I don't think ANY temple marriage in which the spouses do NOT become one is a celestial marriage - and I believe ANY non-temple marriage in which the spouses truly do become one IS a celestial marriage. The latter simply hasn't been ratified by God yet (when viewed from a classic Mormon perspective). I view proxy temple work as a validation of this concept - that God will ratify those marriages where the couple became one, even if they were not sealed in this life.
I know there are situations in which becoming one simply isn't possible, for one reason or another - and I also recognize that there are some marriages from which one spouse simply must flee in order to have a chance at the type of relationship I am describing. However, I can't fathom God tearing apart a couple that has managed to become one solely because one of the partners wasn't totally on board with the religious theology of their time or their spouse. I personally think those who become Christ-like / godly in this life (or who strive to become so) will have "a multitude of sins" covered by the Atonement - and becoming one as a couple, where possible, is a key part of that "covering", imo.
Also, I HIGHLY recommend watching the movie "What Dreams May Come" - and focusing intently on the part near the end where the husband explains to his wife why he won't leave her in (literal) Hell (after leaving her in her previous figurative Hell) - why living in Hell with her is better than living in Heaven alone. (It's instructive that Adam chose to leave "paradise" in order to be with Eve, when the other choice was to remain in the presence of God without her.) If wives and husbands could see the incredibly deep and profound message I took from that scene . . . I think much, if not all, of their collective angst and concern would vanish - and they could tackle life together with faith that they will remain together eternally simply because they won't accept anything else.
(Fwiw, that's how I feel about my wife: ain't nobody going to split us apart, 'cause we are welding ourselves into one being.)