My (28F) boyfriend (32M) and I are having a disagreement about what he said to my mother. Can anyone help me see this from his side?

My boyfriend Joe and I were over at my parents house last weekend for dinner. he went in the kitchen to "talk" to my mom. I asked him what they were talking about. They both told me I didn't need to know. So I waited for them to tell me. On the way home Joe told me that my mom asked him his "intentions" with me. Now I don't mind that she asked him that, but I do think it's kind of odd that he told her "There's no need to worry about that ma'am." I feel like maybe he told her more then he's letting on to me. I asked him if he was saying he's not planning on proposing to me. He told me I didn't need to worry about that but he did say he doesn't plan on getting married anytime soon. I'm really upset over what he said. He asked me why it mattered if he ever got married or not. I told him it's not that big of a deal to me but I feel like he told my mom he had no intentions of marrying me. He told me that whatever he told my mom was between the two of them and I had no business knowing so I should just be happy we're together. I can't help but feel like he insulted me. Can I get your feed back on this situation?