Realize that YOU have control over what YOU do. If you think you will fight and don't want to, then don't answer her calls/email. It's up to you, it really is. Sure, she may get upset. If she does, you can calmly explain that you didn't answer because you didn't have time to give her the attention she deserved. If she brings up the "issue" you don't want to fight about, simply say your peace calmly and then stop the conversation. Do not defend yourself, and do not clarify what you said. Let her rant and rave and if she does, listen as long as you want and then end the conversation.
You (and me for that matter) need to stop worrying about her getting upset because you do x, y or z.
