Sirius when you break up with him.

"I'm sorry, Sirius. I can't do this anymore." You said, holding back tears as you looked at him. His face fell, he took a sharp breath.

"What? Why not? No, (y/n) Please don't do this." He pleaded, tears forming in his eyes. But you had too, for his own protection.

"I'm sorry." You muttered, leaving Sirius crying as he watched you, the love of his life, leave.