Dear Rafael:
I think that it is fair that you choose this week in that other city to be exclusively dedicated to your professional development and not spend any of it with your boyfriend. In most instances we have to look for what is good for us first, as our first priority.
In some emergency situations, let’s say your boyfriend is sick and there is no one to take care of him, so you postpone that week in the other city and spend it with him. But in the circumstance you outlined, there is no emergency (and you are not choosing to party without him). So it is fair that you do what is right for you.
anita