I realize that the reminder might cause unwanted emotion so soon after a breakup, but as long as it's easy to permanently dismiss the reminder, I would guess that the informativeness of the reminders when they were applicable far outweighed the brief heartache. But then again, I generally prefer to be given a stream of relevant information forthrightly and unfiltered, whether from humans or machines. I'll take the convenience even if it comes with the occasional unpleasantness.

But just wait. Someone will be really freaked out when one Thursday Google fails to show him the traffic to the girlfriend's house, then when he gets there, she breaks up with him.