In BrE, would you place the comma inside or outside of the introductory quotes ('I' and 'That') as I've done below? 'I', he said, 'am disgusted with her.' 'That', he said, 'is deplorable.' Thank you.
Traditionally, as you've written it, but many (most?) British fiction publishers would stick it inside. I would put it inside as if there were a natural comma there. But my choice is purely stylistic. If you have an editor, ask them, they'll settle it for you.