The lady appears to have played the entitlement / DYKWIA card a little, which may well get short shrift ex-UK.. But then again, wouldn't most couples having openly admitted selecting those seats to play empty middle seat roulette, and lost, just then invite the third person to sit window or aisle so the twosome could sit next to each other anyway? Digging heels in about wanting the difficult passenger to sit between them for an hour or two just as a point of principle seems a little strange. Perhaps that was a manoeuvre to somehow get the middle seat made empty again. Each to their own of course but IMO there's something a little odd about this whole tale.