I believe in the heat of a break up, it's too easy to fall into the mind trap, that we meant absolutely nothing. It takes away from self worth. And it's a falsehood. It's a negative take. Our self worth transcends whether a relationship makes or breaks. Something to address in therapy or through self help work. CBT mainly.
Is self defined by having a relationship? I'd err to say, self is not defined by having a relationship. Thus, self isn't defined by not having one.

((((Gentle Hugs))))