I strongly urge you to see a couples counselor together. Someone needs to help the two of you make sense of the huge change in your relationship. My only guess is that you moved in together much too soon. You both must have been quite infatuated with each other.
The trouble with infatuation is that it doesn’t let people see each other clearly. Once it settles down, people often see each other in a new way. What was dismissed because of the excitement of new love then becomes more important. It could be that the two of you are experiencing the change in different ways. You still like what you see. He has some serious questions.
I don’t know if the two of you will move to the next stage. I do know you need some help getting through this impasse. For that reason, I do urge you to see someone who can help you sort things out.
I wish you well.