In regards to the letter, I obviously can't say with any certainty whether it's a good idea or not, as I do not know you or your significant other, but I can relay to you my own experience. I do not enjoy talking about feelings, I do not understand them and I'm not sure I experience them the same way others do. I don't just dislike talking about them, I do not know how. When I try to verbally communicate what I'm feeling, face to face, everything becomes muddled and I get frustrated. One of the ways over the course of my relationship with my wife, going back to the first few weeks we were dating that I've relayed what she means to me and why I want her in my life, is through sitting down and writing out carefully considered letters explaining what it is I enjoy about her, how I feel around her, how I envision our future together, et cetera and then giving them to her. These letters mean a great deal to her, and she understands I can best express my innermost feelings in this manner rather than trying to sit down and discuss them with her.