Billy and Stu’s dynamic is so much more interesting when you explore the idea of “even the creator wasn’t sure if Billy loved Stu back.” Not in a toxic yaoi way. But in a genuine character analysis of “is Billy capable of loving another person, even in his own broken way.”
I think that boys personhood was deeply interrupted by personal tragedy and completely sidelined by violent ideology to cope with the former. Billy you are such a freak and I love you deeply. You are not a functioning person, but Stu is SO INTO IT.
Because when you frame it in this way too, you enter ideas like “if Billy did love Stu back, was his way of showing it inherently being ghostface together. Almost a form of vulnerability he often can’t share. Being something together separated him from his personal identity he had all those issues with, and made something new he could just enjoy.”
You can assume Billy has issues with things like physical intimacy because of his family’s past as well as the fact he viewed sleeping with Sidney as something almost like a task or trophy. It was something to check off before he killed her to fully get back at her and her mother. Sex isn’t a romantic thing for him. It’s what ruins someone’s life, because it’s something you just stupidly do.
Men are supposed to want to sleep with women. His father broke up their home for it. Sidney is supposed to be like her mother in his mind. Hell even Randy only hangs around hoping to get a girlfriend. Stu is also a big player in the school and we know for a fact has slept around or at least dated multiple girls. To Billy, sex is impulse, greedy, and selfish. And I’d imagine he views any romantic interaction as “just the start of the same bullshit.”
I also love pointing out it’s in the party scene/end of moving, and a little with Randy in the movie rental store, that we see Billy actually expressing himself. He smiles, he gets passionate. He feels more alive. Whereas any time he’s with Sidney alone, with the police, or at school, he takes on this more monotone (what we as the viewers first interpret as “cool”) almost hollowness.
Those are also the moments we see Stu get REAL excited. Even when he welcomes Billy into his house at the party, that dude can’t contain himself. He knows he’s about to see BILLY. The real him.
These are also the times they are closest to each other. If Billy does love Stu, he hides it deep in himself. He has complicated weird feelings about relationships. Honestly it’s probably easiest for him to functionally love Stu out of anyone else. And Stu is probably able to understand that better than even Billy himself. Stu WANTS Billy. He says he’s easily influenced but in reality the only thing that influenced him was how badly he wanted to be close to this man.