Thank you for bringing this question to Just Answer.
I see some red flags in your description of your fiance. Specifically, and most worrisome is his inability to respect your boundaries.
When someone in a position to meet many people (like the owner of a bookstore) has been alone for many years, it may be that others recognized his somewhat narcissistic traits and chose not to persue a relationship.
Merely being alone for years does not make one forget how to respect boundaries, keep on conversation on topic, or listen to other's opinions. These are personality traits, and by the time one is an adult, these traits are difficult to change--even with therapy.
Remember that you too were alone for much of your life, and it didn't make you feel entitled to free labor from him, or to bring every conversation back to yourself.
You may want to read some descriptions of narcissistic personality disorder and see if they ring true to you about him. This is a difficult disorder to treat, and most difficult is getting the person to understand that they have a problem.
Your description of his behavior sounds more like entitlement than neediness. In any case, at this age, what you see is what you will get if you continue this relationship. Take a good look at what you are getting out of being with this man--
Does he make you feel like your best self? Do you feel respected and admired?Do you feel that he "has your back" and would be there for you if you were in need?
If the answers are yes, then perhaps it's worth putting up with his entitled behavior. If not, you may want to think long and hard before signing up for a lifetime of typing for him. Suggest that he hire someone to do his data entry--his reaction will tell you a lot about what he thinks he is "owed" in a relationship.
Regardless of our fantasies, loving a person will not make or help them change. The only one we can change is ourselves Either you are getting enough out of this relationship that it would be worth changing your perspective on his behavior, or you need to realize that this relationship will continue to be all about him, and decide if you can live with that. What you have now is what you will continue to have, especially when married.
It might help to talk this out with a therapist in person. Here's a link to help you find someone local if you decide it would be helpful.
I wish you all the best,