I don't know wether he has second thoughts, you guys sound like me and my fella only the other way around.
I am definitely an, only do it when I absolutely have too, kind of person.
He is highly motivated and a bit OCd.
I drive him to utter distraction, which is why even after 3 years of knowing each other, and a year of being together we have Zero plans to move in together.

I can't be doing, with his fussing and nipping at my heels, and my virtually horizontal attitude to life would undoubtedly drive him up the wall.
He like you seems to think everyone should find it simple to be like him. He sees life as so much easier when regimented, and panics when I simply shrug and say " I don't know, I haven't thought about it."
He would end up doing everything and then resenting me for it.
So we don't go there.
We love each other to bits, but are stubborn and set in our ways. We do the things we both enjoy. But just accept in some ways we aren't compatible.

I think it's important you talk to him and assess wether this is just a personality trait or is it reflecting his feelings toward the relationship or rAther the coming commitment.
Just talk to him.
I will second a previous comment. Living with someone is very very different from knowing them from the outside.
Hope everything works out. Aæll the best.