Are situations are very similar OP.
I have been accused of me wanting her to be my sex slave and not happy unless she has her legs open 24/7. Among other derogatory comments.
This is known as shaming your needs. Feels terrible. After awhile you may start to think that there is something wrong with you and you may wonder if you are treating your wife badly because of how she says she feels.(?)
When she says "welcome to married life". What she means is "welcome to married life with me". When she says "married couples don't do that" she means "anyone married to me will not be receiving or giving that sexual act." There are in fact a lot of happily married couples engaging in good frequency and variety. Maybe what she is trying to tell you is that all married men are miserable with their sex lives. Perhaps ask her if thats what she means.
I will submit that she has never had her legs open 24/7. In that case her nickname should be 7/11 and it's not. If she wishes to know how you feel she should ask rather than project how she thinks you feel and in the same breath shaming you. I would suggest in a calm manner ask her for some respect. That if she wishes to know how you feel you are asking her to ask you rather than assume, because sex slaves dress and behave differently than she does....
In your case as in mine divorce and or separation has to be an answer for your difficulties. Where will you be if you find out from her that she is not attracted to you? What choice will you have if you wish to live your life with a partner who is interested in you sexually?
My wife and I are at that cross roads due to my severe destabilizing of our marriage. I cannot go back and live the way I was with her. It is not healthy for me at all. And it's really nice to be able to let go of that resentment and anger. Although it still creeps in now and again it is getting a lot easier.