He and his family sound pretty great. I forget, Liz, do you see a therapist on your own? If not, that might be helpful in terms of sorting out your feelings and your fears.
And I agree with dandylion, take your time. It's fine to be excited about seeing him, and enjoying your time together, but take your time about moving in with him or marrying him. If the subject comes up, you can just remind him you JUST ended a marriage and you want to be sure you're on your own two feet before you jump with both of them into a new one. I think 18 months actually sounds about right. There shouldn't be any rush about it.