How people end relationships with you says a lot about how they would have conducted themselves within relationships if given the chance. If they chose to duck out in a way that you find disrespectful or cruel, just imagine how much worse being in a relationship would have been.
You don’t regret the relationship that wasn’t. You’re mad that they disrespected you.
You think a romance will get your self esteem back. In reality, you don’t want love, you want revenge.