Why did my boyfriend respond this way to a compliment?

During a date, I noticed a woman who was really checking out my boyfriend (I'm 41 and he is 45). I was flattered that another woman thought my guy attractive. I smiled & said to him: "Did you see that woman checking you out? Hmmmm. My boyfriend has always told me that woman never approach him, so I thought it would boost his ego a bit. The problem is he actually got angry and said that my comment made me appear to be jealous. I don't know what to think about his comment; other than it is just weird. Is this a normal response for a compliment?