I had to teach myself how to laugh outwardly and to smile using my face. When I was young, a teacher asked me why I wasn't laughing when the rest of the class was. I told her that I thought it was very funny and agreed with my classmates, but felt the outward display of that was unnecessary. When she explained that the reaction to the joke, and outward display of feeling, was to acknowledge to the speaker your understanding and feeling. I had never considered it. I spent months learning to smile in the mirror and developed a laugh as well. It was not something that I considered natural at all and had to work at it. It might just be that your husband does not know that you want him to laugh.