"Failed relationships" refers to romantic or interpersonal connections that didn't work out or didn't last. It implies that the people involved were not able to maintain a successful or fulfilling partnership over time. Full definition
I've never really understood why some men can't let go of failed relationships. (rottentomatoes.com)
However, medication use alone often results in failed relationships, financial demise, and continued symptoms of depression and anxiety. (newharbinger.com)
It stands as a sort of a monument of the artist's several days of drinking in her bed, caused by severe depression over failed relationship. (widewalls.ch)