Dont send her that letter. It makes you sound needy and weak.
Dont make things easy for her. She wants to get a divorce and you cant stop her. But you can start by making her feel some of the consequences of the future as a single mother. Continuing to help her out (ie Costco membership) is not something you should be doing. Separate the finances if you have not already done so.
Move forward as a confident single guy with a daughter. Dont focus on the past. If you make yourself and your daughter happy, that is the best possible thing that could cause your W to reconsider before the D is final.
