I'm really sorry this happened to you. I agree that he probably didn't mean it as an insult. People don't always understand, especially when your stutter is mostly under control. My husband once teased me about mine, and even though I'm pretty relaxed about it with him, I was surprised by how much it hurt. My stutter may be a part of me and in general it doesn't bother me, but being mocked about it, even in jest, just really hurt. Is it worth explaining to him that you have a stutter? If he's a good guy, that's all it will take.