I hope you take that letter to heart, and look at it from a solution oriented point of view.
I can see phrases from DR in your posts, so you must have read the book.
I would suggest you spend some time really writing down an action plan for what sort of things you are going to do to show your wife these things. Start with goals, the same way DR does.
Actually, let me step back, have you actually wrote out the exercises in DR, such as what your goals are, how you can measure progress, etc?
I didn't get a chance to read your whole story - but just wanted to let you know that I also suffered from depression which was a major contributing factor to the downfall of my marriage, as I was completely unable to respond in a positive way to my wife when she gave me the warning signs. I feel a lot of shame and guilt about that.
Me: 35 Her (WAW): 34 D8, S5, D2 T:16, M:9 BD + D: 4/3/2015 EA Confirmed 5/6/2015 Separation under the same roof