A deal's a deal.
A few years back, Rome fell into debt to your family. Unable to pay it back, you came up with another solution.
You came from a long line of pure blooded vampires, a breed that struggled to leave anywhere during sunlit hours without some sort of shade and needed blood to satiate hunger a lot more than normal vampires. However, because of this, your kind was stronger during the night than any other.
Your deal with Rome is that he would work for your family, like normal, but to pay off his debt, you'd feed from him whenever needed. He was your human blood bag.
And, after a long night, he felt your presence behind him and instantly knew what was coming next. He instantly tugged his collar to the side and presented his neck to you.