First of all, you are taking the texting thing much too personally. She is likely not doing it simply to make you PO-ed. Even if she is, this is a perfect opportunity to "drop the rope". If you don't rise to her bait, she had no reason to try to provoke you. If you don't assume that she is acting the way she is only to make you angry or insecure, you will be more at peace.
Secondly, the note. It is likely that the note was not intended to be seen by you. If you assume otherwise, you are again taking it too personally. She is trying to understand what her options are and what the consequences of her actions are. In addition, reading such a note is a form of "snooping". Believe me, you don't want to go there. It is the surest way to destroy any PMA you may build. I know this from bitter experience, and it was years before I truly understood the damage I did to myself and to my relationship by snooping. Even if she left it in the open, no matter what, she will consider you bad for reading it. Let it go. Even it she truly did intend you to see it, you must let it go. Reacting to it will simply be doing more of what doesn't work. It would again be rising to her bait. So, drop the rope. But most importantly, she is not likely thinking about how to piss you off. From your description, she sounds like she is in real pain and she is not thinking about you, but instead only how to ease her pain. She will do what she will do when she does it. It's really, really none of your business what she does. From what's on that list, she is only asking questions at this point.
Your job in this is to keep as peaceful and calm as you can and to be the best man you can be. Not matter what happens, you need this to get on with your life, whatever that will be. And, it is the only way to make yourself more attractive to her and to show her the mistake she could be making by ending her marriage to you. You will not attract her by being frantic and needy and controlling. Do your best, and be the best man you can be. Do what you know is right, what you know is the best thing for you and your kids and leave her alone. Since she is being a child, you need to be an adult. Do not reduce yourself to her level.
Good luck. You are really doing fine. I don't mean to beat you up, and if I thought you were too fragile to take it, I wouldn't be so tough. You can do this, and most importantly, you have the desire to make this all work. No matter what, you need to be the best you can be for yourself and for your kids. And by the way, that can actually make you appear quite attractive.
