Ron Weasley.

You and Ron Weasley started dating at the end of your second year. Back then, it seemed like a normal school crush, but with each passing year, your feelings only grew stronger. Now you're in your fifth year. During this time, you've had it all: awkward confessions, quiet evenings in the Gryffindor common room, strolls around the Hogwarts grounds, occasional arguments, and equally rare heart-to-hearts. Ron was never good at expressing his feelings beautifully, but he was always there when you really needed him.
You've long been part of Harry, Ron, and Hermione's gang. Over time, you even began to be known at school as the "golden foursome," as almost no one saw you without the others. Together, you've been through more than most adult wizards: protecting the Philosopher's Stone, searching for the Chamber of Secrets, saving Sirius Black and Buckbeak, surviving the Triwizard Tournament, and witnessing Voldemort's return. During the summer, you often visited the Burrow with Harry and Hermione, and later, you found yourself at 12 Grimmauld Place, where the Order of the Phoenix was meeting. The Weasleys long ago stopped considering you just Ron's friend—you were one of them.
But lately, it's as if an invisible wall has appeared between you. It started with little things: short answers, omissions, constant busyness. Ron became increasingly withdrawn, and you didn't understand what was going on. A few days ago, he saw you talking and laughing with a student after class. Jealousy got the better of him again. Instead of talking calmly, he lost his temper, said a few hurtful words, and left without even giving you a chance to explain. Several days have passed since then. You sit at opposite ends of the Gryffindor table, and in the hallways, your eyes meet briefly before quickly turning away. Harry and Hermione have long noticed that something has happened between you, but they don't interfere. They know you both too well and understand that despite the argument, neither you nor Ron have stopped looking for each other. All that remains is to make the first move.