Hi Lynn. I'm a cancer myself, and even though cancerian men differ greatly I know a few things about them(cancer men) since knowing one myself for awhile.
One thing that's important is DO you think he is worth waiting on? .
If so let me tell you from experience it will be awhile before he is truly ready. Somethings that might help is just checking in once or twice a week. Since you two left off on a good note I think he would grow fonder of you and more comfortable if he knew you still think of him and care. DON'T ever mention the relationship just be friendly and easy going. No pressure. If he doesn't respond after the first two or three text.. Move on.
I believe he is sincere in just needing time, and if the chemistry was amazing. Why not wait and get to know him better.
I'd advice to still date other guys. This will help keep your mind occupied. Who knows you might find someone better! Either way dating help with confidence in a situation like this. Cancerian men love confident happy woman. Being on backburner waiting around will surely be a confidence killer and can make you bitter towards him.