I don't 'dress' or act 'womanly' enough

Elizabeth
My SO is always saying that I never dress womanly enough or act like a grown up female. I'm 28, he's 31, I only dress up specifically for special occasions and have a wardrobe full of dresses which I would wear only for special occasions. I am a petite lady and do really dress to feel comfortable
Not follow any fashion trends...the thing is he wants me to be like the women he sees in an office or in movies and he thinks I need to dress like this 24/7! Don't get me wrong I do dress up in the bedroom..stockings, suspenders and all that but do I constantly have to look sexy all the time! He did say the other night he barely sees me as a woman because I don't dress like one! It does get on my nerves and I'm not gonna change who I am for any man but I need advice on what to say if he brings it up again?!