AIO? Boyfriend (24M) thinks my “cankles” (22F) are a turn off?..

So me (22F) and my boyfriend (24M) have been doing good recently, but I’ve noticed that whenever we have sex he acts weird about my legs. He made a joke a few weeks back about me having “cankles” and I blew it off because we usually joke around about each other. Anyways, every time we have sex lately I’ve noticed he covers my legs with a blanket or pillows and I found it weird but I blew it off until the other day because it’s a reoccurrence now. This was never an issue in the past until he made that joke. This was his reaction to me bringing it up and it really hurt my feelings to the point where I don’t even believe what I just read. Am I overreacting here?? I don’t think I’m overweight at all and no one’s ever said anything about me having “cankles”? It makes me feel insecure when it comes to sex now. I don’t know what to do at this point and I really love him. We’re supposed to talk tonight, what should I do or say?

TLDR: bf thinks I have cankles and it’s a turn off for him, not sure how to go about this or his response.