Mac was sure there had to be some kinds of rules to having a long distance relationship. With another man, who also happened to be a police officer.
After two wonderful weeks in Miami with Horatio he'd come back to New York with questions. Not about Horatio or where they stood with one another. He was sure of those. No his questions were more about how it would work. If and how they would tell their friends. Horatio's parting words to him would be that they would work it out. But he liked rules. They made things easier, especially relationships.