The choice is what's been presented as the challenge. This is the first instance of the example choice being part of a larger, interconnected story. Even there, I'm not clear on what you think the challenge is, or how the choice leads to success or failure at the challenge rather than just another part of a larger choice tree. I can see choice as part of an actual challenge only if you're making the choice blind or partly blind as to whether or not it will lead to ultimate success at the overarching goal. What I don't see is your duality of challenge being either maintain your purity or get the girl -- this is a naked choice, not a challenge. There's no fail state here, nor is there a success state, it's just a choice between two different states.
To illuminate, swap your goals to a) get the piece of pumpkin pie, and b) get the piece of apple pie. Either way you get a piece of pie and don't get the other, but this isn't a challenge, it's just a choice. For there to be an actual challenge, you have to be able to fail at what you attempt, and there's no attempt here, just a choice between outcomes.