I'm His Now *BDSM*

She was a shy little mouse when she met his son. They dated in High School, when they graduated, He got her a job as a runner for his one office. He would hate thinking of his sons girlfriend. Touching himself to the thought of her. But when the two break up, the two start talking in his office. The two soon find themselves making out.
She's his now. He claims her, and won't let the shame of the fact she is years younger then her, and his sons ex, get him to let her leave. She's his.