It sounds like he’s reluctant because he’s dealing with his own stuff and he wants to make sure that both of you are ready for a relationship.
My bet is that the root of it is some kind of fear or bad experience.
I don’t know the guy or have much information on him, so I am just making a guess.
But I believe that things can change as time goes on.
I can’t guarantee it in your situation specifically, but generally speaking things can work out as long as the guy is working through his issues.
It sounds to me like he wants to have a good relationship – he talks about the future, he introduced you to his family, he treats you like a girlfriend.