Mathieu Amalric is superb as Paul Dedalus, the central character of the film. (Amalric is excellent in any movie, actually.) Paul is a graduate student instructor who is brilliant, but lazy, and undecided in all the major areas of his life. He is too afraid to dedicate himself to a career as a professor, so he has been delaying writing his doctoral thesis for years. Though he has been with Esther for ten years, that does not indicate any form of commitment on his end, as he will not let the relationship mature or change in any form; he cannot break up with her, and he cannot remain faithful to her. Paul idolizes his only friend, Nathan, a professor of the same age who is not as brilliant as Paul, but has had the admirable drive to at least complete his thesis and secure a teaching post at the university. At the same time, Paul despises his ex-best friend Frederic, who is nearly as bright as Paul, but has an obsessive ambition and forceful ego that have propelled him to department chair over Paul. Paul has affairs with Nathan's girlfriend Sylvia, and her sister-in-law Valerie (both of whom have emotional/mental problems of their own), justifying that each one is better than Esther because they either have a job, a place of their own, and/or educational goals (none of which Paul really has for himself). Paul fancies himself Esther's rock, and eventually dumps her because "no one can carry the weight of someone else's responsibilities." The story, which switches between the present time, a few months earlier, and a year earlier, shows how Karma whips Paul around a bit, and forces him to come to terms with his insecurities, his future, and most importantly, his love for Esther.

Paul may be the main character, but Esther (a wonderful performance from the little-seen Emmanuelle Devos) is the true hero of the film. Desplechin's direction is so subtle, yet precise, that at the beginning of the film, we aren't even aware that we are seeing Esther through Paul's eyes: At first, Esther is needy, whiney, suffocating and ugly (a reflection on his esteem for her). But in the middle of the film, after the break up, we see Esther bloom. She all of a sudden becomes stunning, but not through any superficial changes. We see Esther as she truly is: Beautiful, intelligent, and completely self-sufficient, with an amazing and quiet courage. Paul may not be able to carry her responsibility, but all along, it was actually she who carried his. Her greatest fault, as well as her best quality and strength, is her love for Paul, which he is too blind to see at first, then later realizes. (Another credit to Desplechin's direction: Even when Esther is most angry at Paul, you unconsciously see him through her eyes, and see just how charming and intelligent she thinks him to be.) If you're a girl whose heart has been broken, you will relate to Esther's silent moments, her wailing moments, and her struggle to move on with her life.

Don't expect things to tie up neatly; real life never resolves itself in simple, concrete ways, and neither do French films. Along with Esther and Paul's doings, we also peek into the lives of Paul's friends and family members, who are all in their mid-twenties and early thirties, and are similarly at crossroads-with-no-signs points in their lives. This large cast of characters plays out the problem of intellectual youth: As bright as they are about academic matters, they are ignorant when it comes to human relationships, including the way they view themselves. Probably also attributed to the otherwise admirable French qualities of discussion and debate, they rationalize or theorize too much on their problems and situations in order to avoid making decisions or taking responsibility for their actions.

Do not be put off by the serious and cerebral topics of this film: It is extremely funny, but in an intelligent sort of way. Very little of the humor is physical or circumstantial (although it does have its moments where you will burst out laughing, such as the scene where the monkey gets stuck behind the heater, which a previous reviewer mentioned).

"My Sex Life" also offers an alternative view to Paris; it is the setting for all of Paul's romantic moments, but the city has never looked so grey, which reflects the loneliness of the students' lives as they struggle to find love, while blind to the love that is already there. No glamourous scenes, no sunny makes-you-happy-to-be-alive moments; this movie is as gritty as real life, and just as interesting.