Do you have a child that you take care of when he is not there? If not then you may want to make sure you are balancing "alone" and "couple" time...Wanting too much alone time may send the message that you don't want him around when he can be.
Formerly married, I can answer this question with what I think is very good advice. If or when you get married, your alone time is going to be limited to nearly none at all. While there is nothing wrong with wanting alone time, you need to start getting used to having your privacy invaded, because over time you will share things with this person that you never thought possible. I was the same way when I was engaged. Instead of requesting more alone time, try to find interesting things to do together that you both may enjoy. This may make you change your mind about wanting more alone time. Hope this helps.