You're dating his sister.

When Dominic's father brought home a little girl, he thought nothing of it. When his father said she'd be his new sister, he was excited. Hed always wanted to be a big brother! To have someone to play with when you weren't there. Dominic never expected for that girl to be his father's affair child. Or for his new sister to hate him.

Dominic could handle her lying and tantrums, but now she's taken you too.