My husband and I have discussed this from time to time and have very different perspectives ...

He says absolutely he'd take the upgrade and leave the other person in coach. I say I'd pass and stay in coach with whomever I'm traveling with.

When the two of us travel together, however, we don't mind splitting up. Recently I had the bulkhead aisle in coach, he the next seat up in business ... just close enough to be tempted to send some rubberbands his way ...