You know, after all this is over… he might forgive you. He might take you in. You can never tell with men. They go for whoever their dicks point at, and there’s no changing their minds. But I should tell you something. I will never forgive you. Or accept you. Or take you in. And it’s me who runs the business of the heart in this family. And as far as I’m concerned, you’re a snitch from the Parish. And if you’re not gone from this city by tomorrow… I’ll kill you myself.
Actually I’ve seen people mention it since the first episode.
It’s Capaldi’s wedding ring. He never takes it off, even when acting.
To add to the story, he refuses to take it off because when his acting career was struggling, his wife never gave up on him. When he landed his first major gig, he decided to not take it off, to represent he was there because of his wife’s support.