Was my boyfriend rude for saying this, or am I being too sensitive?

Last night my boyfriend and I came upon the subject of.... And then he started talking about his two ex-girlfriends' s, and mine. He said, "Nancy's were a nice size, but they were too squishy. I would rate them as a B. Your s are nice...they're firm, but they could be bigger. I would rate them as a B+. But Kaylee's were perfect. They were a good size, they were firm, and they were perky. I'd give them an A." At first I didn't say anything...I just got all quiet, and that's how he could tell I was upset so he asked what was wrong. I told him that he should really think about things before he says them, and consider people's feelings more. He got all defensive and told me I was just being too sensitive, and said, "So what if I liked Kaylee's s better." Was he rude for telling me my could be bigger and that "Kaylee's" were better, or am I overreacting? What should I tell him?