And I have given up my seat in past to permit a terrified spouse to sit with their partner, unasked, and unexpected on the part of the passenger.

Yet still there are many here who feel that they are morally superior because we won't do that every time.

I'd also like to point out that to many of us, even asking is not something we like to do as we feel that simply asking imposes on others. I did ask once in my life, when I was a very young, inexperienced flyer, and the response from the woman was so vitriolic and harsh that I never asked again. I also learned from that experience and don't feel that it is right for me to impose on someone else and put them in a position where they may feel obliged to do something because of my issues.

For me personally, if I were you and your wife in that situation, I still wouldn't ask another passenger. I would do everything possible before boarding the flight, and if when boarding was completed there still were no options ie empty seats, I would weigh my personal needs against deplaning.