Sher is terrified of commitment but he's also absolutely terrified of being used for sex, of having someone he cares about just have sex with him again and again and his feelings never mattering, of his feelings growing stronger because of sex but not being anywhere else.
Fah kissing him during the confession terrified him. Because it added sex to love and to friendship and to affection and Sher just doesn't know how to handle all of that, how to put it all together.
Honestly, this dynamic is really, really working for me. Fah is a player who fell hard in love because he's been hoping to for a long time and Sher is terrified of love and so he became a player to avoid it but has fallen anyway and doesn't know how to handle it.
Sher is trying to stick Fah into a safe friendzone for his own sake, because it's safe to be friends and not lovers, because friends are safe. He doesn't want the risks of being in love or having a lover. But he already does with Fah and that scares him even more.
But once Fah falls in love it's all he wants. He just wants to love and to be loved and he doesn't understand what's to fear about love or being in a relationship because they're just part of his life. He falls in love and he prepares to fall out of love. He was clear about that, about how much he loves but he's sure everything ends.
Oh, the contrast.
Fah has just accepted that everything ends while Sher can't bear the idea of love ending.
