In original novel, Ralph (Raoul) and Chris (Christine) basically knew each other when they were younger. They were not lovers or close in adulthood like they seem to be in this AU.
They do reunite when Chris takes on a major role at the theater and things romantically blossom further from there.
There is nothing actually sexual in the original novel.
(Actually Erik/The Phantom is older and horribly disfigured, missing a nose and corpse-like in appearance. Not hung like a horse with washboard abs and Fuck Me gloves).
The reason Chris(tine) is so trusting/accepting of Erik/The Phantom is because in the og novel Chris(tine) is deeply devoted to the memory of dead father who said he would send the Angel of Music as a guide. So Chris firmly believes that the Angel of Music is heaven sent from dad. (Erik/The Phantom takes advantage of this and pretends to be the Angel to get close - this happens in og novel as well).
But when things start getting sketchy (like people getting killed and weird shit happening, Chris(tine) starts to fear the 'Angel'.
I don't wanna put any more info for now and risk spoilers for later. But I hope that helped a little.
I haven't read/watched the phantom of the opera but this story is one if not the weirdest I've read so far, including BGs (saying a lot)
Like, I want to know if the inspiration is as weird and therefore the comic as well, or there are actually brain holes in this omg.
Like, how can he say to love Ralph so much as his fated pair but be so inclined to loving/being loved by another unknown alpha? How I his shadow towards alphas after all that SA (absolutely crazy frequency, was it all needed?) So targeted to ignore Ralpha and the phantom? He's so... naive in nice words. But at the same time good at grasping that his rivals and enemies are being taken out and take advantage of that to get a main role... Ah, it's not THAT BAD, or my tolerance is great, but this is confusing.