What goes around comes around, in more ways than one. The female character with barely any lines really does eventually get fed up with the second male lead pestering her.
The female character: “Can’t you go back to treating me like I didn’t exist, like you used to?”
The second male lead raises an eyebrow. “Back then, you insisted on sticking by my side, and I let you have your way. Now you want to leave me, and I’m supposed to let you have your way again? Why don’t you let me have mine for once?”
The female character: “...”