I absolutely agree that it's a FF vs. non-FF issue. If you love someone enough to live with them (perhaps a naive assumption! ), why not give them the treat of flying first class when they aren't used to doing so.

As an illustration, I recently flew four segments with my husband and kids. We are all Gold on US (my husband, myself, and my daughter anyway - my son was a lap child on these particular legs), but I have more BIS miles and am therefore higher on the upgrade list. On the four legs, we had 1 upgrade, 2 upgrades, 3 upgrades, and 2 upgrades, respectively. On the three legs where we didn't all upgrade, I called the DM line and switched out my name for my husbands. On the actual flights, we (roughly) alternated who actually flew in first, and how the kids were distributed.

On a funny side note, on one of the legs where I was in first, the First FA went back to my husband and offered to bring him a drink - a nice gesture. Subsequently, on one of the legs where my husband was in first (I was in the first row of econ, so I heard all of this), he asked the FA if he could send me a drink back in coach. She said sure, poured the drink and brought it to me, and then charged me $5!