I have learned to have no expectations as far a my H is concerned. I take nothing for granted anymore. Therefore, his actions or non-actions very seldom affect me. I do validate and thank my H for anything nice or thoughtful that he's done and choose not to call him out on negative behavior. Very little affects me personally and my kids are very good at throwing truth darts to let him know if he's done something that affects them.
For me, I recognize my anger, think about why I'm angry, and work it out for myself. I accept what is, is. I can only control me. I try to handle it in a way so that I personally have no regrets. Yes, forgiveness does enter into it, but you need to deal with it yourself before you can forgive.
If you think what your W has written is a trap, make sure you stay away from the snare. Validating what your W says or feels doesn't mean that you agree with her. You're just accepting that she has a right to feel as she does. You can validate her by saying that you are sorry she feels that way, or that you can understand why she feels as she does. You could also say that you don't remember something quite the way she does when she starts rewriting history. Do more listening than talking. If something she says stings, take a look at it and own your part in it. Fix what you don't like about yourself.
She may be feeling guilty about her spending or she may be angry that you spent the money she was hoping to spend. Don't waste your time over analyzing it.
I see by your sig line that you believe your W has been in MLC for a couple of years? What makes you think that? If she is in MLC please protect your finances because they are notorious spenders. Since your W has left you and you have primary custody of your D, you would be wise to separate your finances so your W does not have free access. You are enabling her new life. She needs to find out what life would be like not to have Arsene in it. A person will not miss what is always there.
You sound like a good and caring man. DBing is many times counter intuitive to what you think you should do. It's hard to get the concepts down and detach. Once you do, you'll find this gets much easier.
You need to read DR as soon as you can. I know getting the book is difficult for you. Remember not to let your W know you're on this site as many WAS would view it as pressure to get them back. It's for you only. Also, when you get the book remember to keep it out of her sight. Otherwise, she'll think all your changes are just tactics.
Make those changes for you because you want to become a better you.
Over on the MLC board at the top is a chapter on MLC out of the DR book. Have you read it? It is the 4th thread down from the top. It may help you determine if W is in MLC or not.
