Just don't force it. Let him become comfortable in his own time. My BF is not a big snake fan, never has been. He doesn't dislike them, and he has no desire to hold any of mine (I've got around 50 of them), but he doesn't complain about them, and I don't have to consult him when I add more (we live together).
He does, however LOVE going to the reptile shows, because he loves the friends we have made through the hobby. He's the one always asking "when's the next reptile show? Where is it going to be?". We're already planning to go to Tinley in October with three other couples, renting a big passenger van to drive up there together.
It really doesn't matter to me that Karl isn't into the snakes like I am. They are my hobby and my passion, he has his own interests and hobbies that I'm not as into. It works for us.