Advice letters about dating so often baffle me with the alienness of their worldview. You've been dating for over a year, LW, with "open and clear" communication, and yet you have never once had a conversation in which she expressed some opinions about gender presentation and expectations? You can't conceive of asking *her* opinion, rather than that of a total stranger, as if women are a monolithic faceless mass with Traps To Avoid (being seen as sexist) rather than individuals with views of their own (an opportunity to learn about someone you care for!).

Your options, LW, as you have presented them:

1) Tell your girlfriend you want a specific gender performance from her.
2) Say nothing and resent her for not giving you what you want spontaneously.

You know what's missing, here? I can hardly read the letter for the howling void of its absence.

Any curiosity at all about what LW's girlfriend thinks or feels about makeup. Any interest at all in *her* specific experience of being a woman who dates and doesn't wear makeup much. I am absolutely sure she has thoughts on this! That there are choices she has consciously made! This... does not appear to occur to LW at all.