He doesn't want to marry me?

Yesterday, we went to my boyfriend's family Christmas dinner (after my family's Christmas brunch). We've been together for three years, and we've lived together for two. His brothers and brothers-in-law teased him about how my hand was naked and that I'd be Mrs. Smith next Christmas. My boyfriend reacted REALLY quickly to say no. I was embarrassed, how quickly and vehemently he said no. We've talked about it before, and it is in the five year plan. Money is tight right now, and he needs a more reliable car very soon. I know realistically that he's just looking at the practical facts here, and he does love me, and he just doesn't like his brothers pushing him. But I can't get the feeling out of my head that he told them the truth.