A month after breaking up, I want to call my ex-boyfriend and say that we can delete each other.

You can't. A month after breaking up, I want to call my ex-boyfriend and say that it is very impossible to delete each other. Even if we break up, even if we don't meet again, please don't delete each other's contact information. As adults, you can restrain yourself from disturbing each other. When you can't put it down, look at each other's recent state. When you put it down, let each other lie quietly in the address book. If you exchange years of feelings for farewell, what have you experienced?