Albus and Gindelwald never parted ways but Albus still became a professor to recruit new blood. Newt is their little darling pet who they've trained into a fuck toy.
I'd love some rough and aggressive fucking but then aftercare, they use Newt but clean him up and praise him, make him adore them. Newt just happy to feel so loved.
Newt a teenager, 16-18 but maybe with references to starting younger