Well, think about the choices for a while. If you find yourself in a situation where this is actually a choice, it becomes clear what you need to do. Anybody that would demand that I give up meat or not get sex is less than a person. Imposing your beliefs on others like this is the prime example of a bad relationship. Once you start giving into these demands your life can only go downhill. Her demands will get more extreme, and you will either lie and live a double life or wind up being completely pussy-whipped into nothing resembling your old self.
And have some pride. We are more than rutting beasts that need to copulate every few hours to satisfy some urge. Enjoy some bacon. There is a nice pork chop waiting for you for dinner. Maybe have some sushi or lobster? Chicken strips sound like a plan. Maybe while you are out enjoying some meat you will find a girl who can appreciate you for who you are and wants to join you at your table for a nice steak, and she will put out for meat.