26M with 26F LTR. My question is regarding the balancing act that takes place in a long term relationship when a male has to walk the thin line between mate guarding and acting aloof. One part wants to set boubdaries while the other wants to remain detached. As an example, my girl recently told me she was excited to go on a river boat cruise party with me. The very next day, when asked by a friend and without hesitation she mentioned she would be taking her sister instead. i could care less about the cruise and who she is going with, however, i felt disrespected that she would say one thing one day and say the complete opposite the next day. part of me wants to remain aloof, detached and let her do her thing, while another part of me wants to lay down the law and let her know its not ok to be flaky with her plans. She is on the cruise this weekend and texting has been nearly non-existant this week. Lift. eat well, remain busy with work and hobbies, but wondering what an appropriate non-emotional response would be? Should i let her reach out, focus on myself until then and act like nothing happened, a-la-stoic manner? Or, distance myself way way way back i.e., 2-3 weeks of busy body?

thanks in advance!