Patrick McGoohan I'd note, had a thing for never playing characters who were romantically involved at all. When he played a spy on "Danger Man" in the early 1960s he insisted on never having any romantic scenes with the beautiful female guest of the week (that moral streak was also why he refused to be considered for the role of 007 when his name was floated as a possibility). You can also see that in "The Prisoner" and even in "Identity Crisis" there is no indication that Nelson Brenner has had any romantic attachments at any time in his life. "Agenda For Murder" is one of the few times I think he ever plays a character who has a wife, but even there you don't see him involved in any moments of personal intimacy.

Ted mentions that good moment when Columbo asks whether someone might have wanted to kill him out of jealousy over a woman, and Rumford not only says no, but gives that funny reaction to the question. Maybe it's reaching, but to me that could be a modest reaction as much as anything else. As in, "Someone jealous of ME?"