" how much your partner believes and supports what you are doing"
Seriously?? One way street, hey baby, let me see how much you support me! I will not be available for you for the next 4 - 5 years, because I am busy becoming a pilot!
What BS talk, seriously, it's not about how much your partner supports you and believes in you, it's about can you have enough time, energy and effort, that when you are exhausted, to also remember she might have a hard time, and that it is not ALL ABOUT YOU!
I am sorry, but I have seen few relations on the rocks or broken because of this business!
Most definitely it does not come down to how much she loves you, it comes down to how selfish will she allow you to be, before she finds out the grass is really greener without you the pilot dreamer!
Of course it does depend if your wife or girlfriend, how attractive they are for others, of course if she is an old sack, who looks like a witch on a broom, you might not have much to fear, however not all of us have wives or girlfriends like that!
If she leaves you, it will be your fault, and not because she did not love you enough - thats just the way it goes, and price of this dream that you might end up both loving and hating!