While re-reading D&C 132 last night at m's suggestion, verses 15-17 stuck out for me. As well as they should I guess, since I am married to my wife but obviously not sealed to her. According to this scripture, the highest we can hope for is to be single angels (not married!) and "ministering servants."
This sucks. To be saved and yet stuck as a servant for eternity really doesn't sound like heaven to me. It sounds insufferably boring.
Also, notice that it specifically states that all unsealed couples will "remain separately and singly... forever and ever." That seems to me to be the real reason we put such emphasis on eternal families, not because non-members think they'll be split up (they don't), but because we do! This is depressing.
We can all agree that God is supremely merciful, so why does he plan on splitting us all up? He says in verse 22 that "few there be that find it [exaltation]." So most of us are going on up to the singles' branch in the sky. What gives?