Would you be persistent and ask him/her to stay or just accept it and move on?

This of course has to be hypothetical...but if my wife decided that she wanted to leave I'd be in a state of complete shock and confusion. I'd definitely want to know why, and yes I would try to do whatever it took and try to convince her to change her mind (who wouldn't?), but if she was dead set on leaving me and the life we have together, there would not be much I could say or do to stop her and I would be totally and completely destroyed.