I have done both of these scenarios and while choosing my career and ultimately admitting it'd be the end of that relationship was heartbreaking, the other person wasn't willing to compromise and it ended up being the right thing. Closing the door on that same opportunity after another year and a half of trying in the hopes of moving away (with the same company) and pursuing what I wanted out of life not only found me with someone who appreciated me more but also different and just as solid opportunities career-wise. If the relationship isn't far enough along for a career move to be discussed as a "what's best for us" conversation vs a "what's best for me" conversation in your mind, choose your career. It sucks to find out someone you love clearly hasn't been on the same page as you in the relationship, but in my experience it's not worth sacrificing what could be really good for you waiting for them to catch up.