I think its way too long. You should be so much more direct. The reason for this is that men tend to tune out by the end of a long emotional letter. I think he will miss the point of the letter.
I know you have so many things you need to say to him, but you should collect yourself a list of the things you need to say to him and do it in person, over time, in counseling or in several direct honest discussions.
In this letter, I think you should simply state your need and your boundary, and tell him that you feel it is on his shoulders to figure out for himself why the intimacy is missing and fix it. Wording it something like "I have this problem and I need your help in fixing it" (longer of course, and more meaningful, but as bare bones and direct as possible).
All the other things that you really do need and deserve to say to him are going to cloud the issue for him and he will not understand that you are trying to have him fix the one thing, instead he will think you are going off in several directions about several past and current issues.
