My husband doesn't really understand my attraction to them either. Today actually was the first time he has ever held one of my snakes. I just explained to him that it is my hobby and that there is very little he can do about me keeping them. I've explained it to people that it is just a hobby. My husband plays squash, goes the gym, take flying lessons whatever. This is mine. I am allowed to have a hobby too. He understands, just doesn't get involved. I am ok with that. I hope that your boyfriend comes to an understanding as well.
Whenever I talk about them, his eyes just glaze over. He is respectful enough to listen but, he doesn't care too much. Maybe tell him that he doesn't have to like but should try to accept it. It is definately rude to hang up on you for talking about it.
My husband has come to like it in a way. He doesn't have to go shopping for me for gifts. He just takes me to get them.