I don't know.... something about the wording smacks of manipulation to me, and your response sounds waaaay too emoitonal. I'd be very careful. Please keep in mind everything in writing has a potential to be used against you in court. I know when I was in divorce I was extremely careful about what I wrote. I felt it was important to keep everything at a VERY emotionless, business-like level. If you have something emotional to convey do it in spoken words in person, not on an answering machine, not on a cell phone. Don't leave a paper trail!!!!
Rather than go into too much detail, if I were in your shoes I'd probably write something like, "I'm sorry this came across as cold. That is not my intention. But for both our records it's important we keep financial details, records and receipts of everything. I truly appreciate your help with this. Please send me a copy of all work and detailed receipts for my records. I will do the same for you. Thank you."
Don't let her engage you in a fight. I think she's trying to do that and you have to keep the business-like tone. She's the one out of control here!!!!
Make sure you keep a copy of all correspondence of this for your records. Including the emotional stuff she's flinging at you. That way, if she does try to set you up for anything you have her correspondence.
Also, the thing about the cash. Tell her you'd like receipts for everything. This is important that you have this information.
There is no arriving, ever. It is all a continual becoming.