Monogamy is pure monotony.
I'm sure I won't be the only critic to make that observation but it needs to be expressed. Some movies that strive for artfulness are mysterious and enigmatic. Some, however, are just plain dull -- like this movie.
Chris Messina plays Theo, a professional photographer who is bored with shooting weddings and other family functions. It's not art; it's barely even craft. But it's a living.
But Theo fancies himself as an artist. So he solicits clients who want him to use his camera on them when they aren't aware. He functions as a private eye, or a spy, hiding and shooting them from a distance (at times when they've alerted him that they'll be at a certain location).
He gets the thrill of being a voyeur in an artful and socially acceptable way. And they get the thrill of - what? Being spied upon? Seeing themselves at vulnerable or unguarded moments? Something like that; he even interprets them to themselves, narrating the photos as he shows them his work.
Then he gets a female client who turns him on. She shows up at the appointed place - a public park - and, as he watches through a telephoto lens, begins to masturbate, while he photographs. Later on, she has him photograph as she is seemingly raped by a strange man.
This is all more than a little bit of a turn-on for him. Indeed, he gets so caught up in this client that he begins to neglect his wife (Rashida Jones), though he only corresponds with the client via email.
And that's it. Writer-director Dana Adam Shapiro wants to make a point about spectators and participants, the thrill of voyeurism and of being observed. But there's just not much there to work with. Theo doesn't talk about it and Messina can't invest the character with any juice to make the photographer interesting in his own right.
It's hard to keep the faith with Monogamy when there's so little there to believe in.