I don't think there is anything wrong with your girlfriend trying to exercise herself. Don't you think the better your girlfriend, the more face you have? If you love her, then she is so busy and tired, you should comfort her and support her. Because of your understanding and comfort, she won't feel tired. Everyone chooses a different lifestyle. Maybe she thinks that can prove the value of her existence. You are her boyfriend and the most important person. If you love her, you should love her lifestyle. If you don't agree with what I said, or you are not happy, then forget that I said anything.