No one really likes to be compared to other people, which is why it is even worse when that is done by the person that needs to be the love of your life. Even worse in a situation like this is when your partner is unfavorably comparing you to other people (if they are of the same sex as you). That could be enough to make any person feel extremely bad about themselves.
If your partner tries doing this on a few different occasions, that could be a problem, as they might continue to do so in the future. If that is the case, you need to have an open and direct conversation regarding the issue. Don't think that just because you don't talk about this, that the issue is going to go away - in many cases, the opposite could be true, and the issue can worsen.