Why do people look down on failed relationships?

I'm so sick of people trying to justify my failed relationships to mean that there's something wrong with me.

Shouldn't it be celebrated that I ended things when I wanted out? That I didn't stick around for someone to walk all over me. That I had the guts to be happy alone than miserable with someone right next to me. That I didn't need someone's attention to feel worthy. That I backed myself and my standards of how I deserve to be treated.