My girlfriend wants to go on vacation alone the same time i'm moving to another country!

So i've been with this girl for more than a year, and i'm now moving back to my home country which is 4 hours by plane from where we are now. I am moving for a better opportunity and i am trying to save money before i go, goal being to marry her in a year or so. Her friends invited us to travel with them to the same place where we are supposed to go in September. Now she wants to go on that vacation without me, in addition to that being around the same time i should be moving. Her idea is that i traveled 3 months ago with my friend for 3 days without her and that she should be able to do the same. Let alone that for so long she claimed she never lied to me, but i just found out she never told me she was speaking to a guy friend of hers and arranging to catch up, just a couple of weeks ago. I broke up with her. What do you think? Mistake?