I'm not going to talk to my ex after she broke up with me
What makes you want to stop talking to your ex?
I'm still a little upset about the thing she said to me before, I thought it shouldn't be a big deal.
It is okay to stop talking to an ex. It is better to stay quite until you can be civil to each other.
You should talk to the ex only when you have forgiven each other.
You have the right idea. It's best to distance yourself until you can heal and move past the hurtful thing that was said. Doing this will ensure that more damage is not done.