Thank you for contacting JustAnswer.
I am sorry to hear about the problems you are experiencing in your relationship. The fact that you can write these feelings and share them with your boyfriend is certainly a positive. In order to begin to feel more comfortable in sharing your feelings without writing them you might try asking yourself what you are worried might happen if you share these feelings with him. Has he responded well when you have written your feelings down? If so, then it sounds as if he could be trusted to hear your feelings in a safe way. Are you expecting that he may react like someone from your past who wasn't able to hear your feelings in a reasonable way? If so, then you may need to remind yourself that he is not like that person. You might try starting to share your feelings by sitting back to back so that you don't have to face him at first. Then gradually begin to turn toward each other to the point that you feel comfortable in eye contact while you share feelings. You might also ask him to share his feelings first.
If these techniques are not helpful for you, then individual therapy could be helpful in working through your issues with emotional intimacy. Books on emotional intimacy could also be helpful. Be patient with yourself in the process. I hope this answer is helpful. Please let me know if I can clarify further.