Jeannine dates Frank casually during her vacation in the Poconos. Like Cal, he calls Jeannine "Jeannie," he isn't particularly good-looking (Jeannine doesn't think so, anyway), and he's not a great conversationalist either. What's he got going for him? Not a whole lot, other than the fact that he's a man and he's available (more or less).
When Frank confesses to Jeannine that's he's married, but separated, Jeannine is willing to give him the benefit of the doubt. But, Frank's statement that his wife is "emotionally disturbed" (6.6.4) should ring some alarm bells. When we're dealing with the pathologizing of women's "hysteria," the phrase "emotionally disturbed" is usually code for "she's not a good enough wife," "she doesn't like sex enough," "she likes sex too much," "she won't do what I tell her," or "she has too many of her own high falutin' ideas."