When I travel with my wife (admittedly not too often), I always booked the two aisle seats in the same row. That way we're close enough to be able to converse and yet neither one of us have to move to the middle seat if we tried the window-aisle combo. In almost 100k miles this year, I have only had two trips where there was an empty seat next to me in all classes. I think the days of using this window-aisle strategy are long gone.