I've enjoyed inflicting pain on people. Does that make me a sadist? Do I need help?

I have memories of hurting my little brother when I was little and recently my boyfriend. I never felt a ual pleasure from it, and I've never hurt my boyfriend for the purpose of ual pleasure. In both cases I was retaliating after feeling disrespected, but both times I took it farther than reasonable because I enjoyed the feeling of being in power, but stopped when I wasn't as angry. Its not like I'd hurt them for no reason. Am I a sadist?