Firstly, the ball is in your court. You are in charge of your own self-development.
Do you want to know how to comport yourself? Is it important to you? If so, ask yourself why. Are they strong enough and valid reasons?
If you decide you would like to improve the way you comport yourself maybe you could reflect on his comments.
Secondly, what is your true nature? Maybe you are not naturally a traditional style lady and are more creative, sporty or dramatic.
In which case, you will have to develop your own version of ladylike.
No-one should try to mold you into something you don't feel comfortable being.
If your boyfriend doesn't love you for your true nature, maybe he needs to consider whether you are the one for him.
Take a look at a website "Dressing Your Truth" by Carrol Tuttle. It may help you understand your nature and your boyfriend's nature and how to appreciate each other's strengths and weaknesses.