Change the pronouns from her to you and this seems like an excellent starting point for your email. I try and focus less these days on sounding coherent or fluent and focus more on writing out the unfiltered and often ill-formed feeling. Sometimes I just list or repeat words and I don't even form sentences.

This sounds like such a frustrating and painful pattern for you - not least because it repeats both with her and on a more universal scale throughout your life. I guess the value would be in working through this with her ... except that becomes nonsensical if she is frequently absent.