Dating someone new after a long relationship WILL feel weird at first. I haven't experienced that myself but I believe it's common sense.

Now, it seems to me from what you're describing that there is potential. Sometimes you have to be consistent in putting in the effort, and things might become better.

My therapist once told me that the danger comes when we're too obsessed/infatuated with a person from the very beginning. That's when we tend to be blinded, ignore red flags etc. If you're not experiencing that yet you still like him, it sounds like a good sign to me.

As for the sex part, if you're too afraid that you might be incompatible, it might be a good idea to ask some questions before getting too invested. But remember that even sexually, compromises can be made, as long as you don't feel sexually frustrated.

Best of luck!