Every one has given their opinion..I am sure you found your answers in one of those. But, I'll give mine anyway.
How badly do you love her?
How badly does she love you?
How badly do you want to grow in your career?
How badly does she wants to see you grow in your career?
These are the questions that would come to anyone's minds generally. Now, face it, you will regret at some-point about the decision you made regardless of what you choose right now, that is life (It would happen to anyone). The question you need to ask yourselves would be...which one is worth the regret?
To answer this question you just have to decide whether or not you love her more than your career or the other way round. Remember one thing mate, their is no right answer or wrong answer in this and their is no good answer or bad answer in this either, good or bad and right or wrong is what you will make of it eventually.
A relation-ship depends on two people and a career depends on the person in question only. Who knows what will happen later on in the relation-ship (it depends on both) but your career? It's always in your hands, you are the one who makes it or breaks it, so why take a chance with something that is not in your hands?
As you said you both have "invested" into the relation-ship, and any investment without returns is a failed investment. But joint investments can always lead to differences in opinions and the business may suffer from a set-back and it might not be your fault, but an individual investment will only depend on you, so you can set the rules and foundations of it all and keep the benefits all for your self. And besides once you gain returns you can always buy what you need from the market anyway.
Now, the important part, those questions I asked in the beginning.. just focus on the first one.
If the answer to that is a 10/10, then whatever I said means shit.. but the fact that you are willing to listen to people explains that you are willing to consider other possibilities and when you have reached that juncture in a relation-ship you cannot take a naive decision and suffer from it and also make the girl suffer from the consequences.
