Think of all the crazy things you did for love. The French call it “amour fou,” and we’ve all had the sickness once of twice (or more). Directed by Ira Sachs and written by Sachs (“Keep the Lights On”), previous collaborator Mauricio Zacharias and Arlette Landmann (“Germinal”), “Passages” tells the not very gripping tale of a love triangle involving meticulous film director Thomas (Franz Rogowski, “Undine”), his gay husband Martin (Ben Wishaw, “No Time to Die”) and a young woman named Agathe (Adele Exarchopoulos, “Blue Is the Warmest Color”) who inadvertently sweeps Thomas off his feet with her beauty and youthful sexuality. It seems Thomas is gay, but not quite entirely gay. Thomas and Agathe meet at a party and cannot keep their hands off one another. The next day, together again, Thomas and Agathe have more sex. At first, Thomas tells Martin about his unfaithfulness with a woman in a way that suggests he cannot believe that he did it, and that it is some sort of grand erotic achievement. Eventually, Martin, a print maker of great talent, takes a new lover in the form of a tall and handsome writer named Amad (Erwan Kepoa Fale). Is the film now a love quadrangle?

Thomas must be one of the most tiresome lead characters in a current film. All he cares about is himself, his needs, his desires, his career. He is not in love with anyone so much as himself, and Rogowski does not have enough screen charisma to make you overlook this shortcoming. The flamboyant wardrobe Thomas wears does not help. These things makes “Passages” a drag in spite of all the sex. Exarchopoulos, who shot to fame as one half of an explicit lesbian love affair opposite Lea Seydoux in “Blue Is the Warmest Color” (2013), brings a let’s-see-how-this-turns-out attitude to Agathe’s affair with Thomas. At first, he begins to move his possessions into her flat. But he comes on to Martin every time he goes to their flat to get his things, even when he knows that Amad is in the bedroom and Agathe is waiting for him. Thomas is flagrantly unfaithful to both Agathe and Martin.

Poor Agathe, she must sleep alone and wonder (not wonder) what is going on and what she is going to do about it. The nature of her dilemma is that she’s a straight woman who has fallen in love with an unfaithful gay man. An art teacher at an elementary school, Agathe’s life is ruled by routine and classes. Thomas, who whirls around Paris on a racing bicycle that could be a metaphor for his flighty, free-wheeling sex drive anxiously awaits news of the latest screenings of his new film. Martin shows his prints to his appreciative patrons. Thomas disrupts both Martin and Agathe at their places of business. Soon, a new, obvious complication arrives. The film is so much like a soap opera, we expect someone to get amnesia (me, perhaps). Englishman Wishaw and German Rogowski speak mostly in English in their scenes together. Exarchopoulos looks like she could throw Thomas, who meets her parents after a night of sex with Martin, out the window, and we wish she would, frankly.

(“Passages” contains profanity and semi-explicit sex scenes)

Rated NC-17. In English and French with subtitles. At the Coolidge Corner.. Grade: B-