Perhaps it's a story about an unexpected friendship or alliance between the wife and two men. Maybe they got involved in a project or a situation together that they hadn't planned on. For example, they could have been brought together by a community event and formed an unlikely bond that led to a series of interesting events.
Well, 'MFM' usually stands for male - female - male in some relationship context. An 'unexpected' story might imply that something out of the ordinary happened in a relationship involving a wife and two males. It could be an unexpected encounter, an unforeseen change in the relationship dynamic, or an unexpected event that affected their interactions.
It could also be that there was some sort of misunderstanding. In a relationship scenario, miscommunication can lead to unexpected situations. The wife might have had different intentions than what the two men thought, or vice versa. This could have created a story full of twists and turns as they all tried to figure out what was really going on.