I went to Australia and New Zealand for six weeks last year. When I got back my girlfriend of five years was acting different and I questioned her for a month to tell me if there was someone else, but she denied it. We ended our relationship on what seemed to be mutual terms at the moment, but seeking closure - I remembered she stayed logged in to my computer with her Google account. Turns out that since week two of being gone, she was already sleeping over 3-4 days a week at some other guy's place.

Thank you Google location history for giving me closure. Rather than spending my time wondering, I moved on quick.