Don Jon stars Joseph Gordon Levitt, who also wrote and directed the film, as Jon Martello, a handsome young working-class Jersey guy who has his pick of willing young women for one-night hook-ups.
But in spite of all the women he sleeps with, he's addicted to watching online pornography. The real women he picks up at dance clubs don't measure up to the fantasy women in the videos he incessantly watches on his laptop, and he's unable to lose himself in real sex the way he does in virtual sex.
And it's this need to lose himself that drives his pornography addiction, just as it drives all addictions.
Like the much less believable character in Fifty Shades Of Grey, the main character in Don Jon needs to exercise control in all things. He cleans his apartment relentlessly, works out at the gym obsessively, never misses Sunday morning Mass or Sunday night dinner at his parents' house. He goes to confession weekly and counts his weight-lifting reps at the gym by saying the Hail Marys and Our Fathers he's been given for penance.
But on weekends Jon goes clubbing with his friends to show off his perfectly sculpted hair and body and check out the women and rate them on a scale of one to ten, being always on the look out for the elusive "dime", or perfect ten among the offerings.
One night Jon finds her, his "dime", a girl name Barbara Sugarman (played by Scarlett Johanson) whose curvaceous body culminates his vision of pornographic perfection.
The only problem is that Barbara refuses to go home and jump into bed with Jon. So he pursues her and takes her out on a date, after which she still won't sleep with him. She makes it clear she won't sleep with him unless it means something.
Barbara's chastity serves to inflame Jon's desire for her and they begin seriously dating, with Jon mistaking his constantly simmering lust for love.
Barbara, meanwhile, has relationship fantasies of her own. While Jon loses himself in lust fantasies of Barbara, Barbara loses herself in romantic fantasies of Jon as the man who lives to please her, fueled by the old-fashioned happily-ever-after Hollywood romance movies she devours the way Jon devours pornography.
In one scene Barbara brags to a group of her girl friends that though they just celebrated their one-month anniversary she and Jon haven't yet "done it", to which her friends reply, sighing enviously, "Oh, that's soooo romantic!"
And so Jon continues to please Barbara - and by extension his parents, who are overjoyed that he's finally found someone - and to please himself by continuing to secretly watch pornography.
All goes well until the moments when Jon and Barbara each in their turn are hit with the reality of the other person who finally emerges from the fantasy.
Ultimately it's from a thin, pale, sad older woman (played by Julianne Moore) whose path crosses with Jon's that he begins to learn that sex is like conversation: it can only be good and engaging with a person you feel comfortable letting down your hair with and opening yourself up to.