You don't owe prettiness to anyone. Not to your
boyfriend/spouse/partner, not to your co-workers, especially not to
random men on the street. You don't owe it to your mother, you don't
owe it to your children, you don't owe it to civilization in general.
Prettiness is not a rent you pay for occupying a space marked "female".
Read more of Erin McKean of A Dress A Day's fabulous essay on the place fashion should take in your priorities.
Guys, please write the male counterpart to this in the comments. Is it just "you don't have to act macho" or can we get to a more specific aspect like "rugged", "tough", "strong"? What is that constraint that brings down the social pressure when you're too gentle and soft?
[Thanks to my good friend Anil for the link and for being the kind of guy who likes to read a post like that and wants to share it]