Let me agree with Sage, in a more blunt fashion.
This is your blog. YOUR blog. The blog that belongs to YOU. This is your place to get things off of your mind/chest, to vent if you need to - and you DO need to do this.
If she CHOOSES to read YOUR blog, that is HER choice - the choice belonging to HER. In this same vein, her reactions to it are HERS - the actions belonging to HER. Not to you.
You choose to write. She chooses to read. She chooses to react. You do not force her to read this or to react to it. Therefore, you have no reason to not write what you feel here, because she can always CHOOSE to not read it, or CHOOSE to react to it in a different manner. She is responsible for her own choices and actions, not you. Your actions and words do not neccesitate a response from her, or force her to react in a certain way.
Keep writing. This is for you, and it's something you need.
This is my family. It may be little, and broken, but it's still good. Yeah, still good.