Why FA avoid/discard their partner after any conflict?

My ex(F) discarded me recently. She broke up with me because I did a mistake(not cheating) and she thinks that she will be hurt again in the future. She can't take that risk and she fully discarded me on a sudden day.

And I realized after every conflict or any issue that could have been solved by a good communication, she used to silent for days. Before our breakup she avoided me for 3 months. I gave big text messages she gave zero values to those.

I want to know from avoidants why you guys avoid your partner if any rough situation occurs in your relation.