[Editor’s Note: Spoilers ahead. Duh.]

Say what you want about the Fifty Shades franchise, but it has forever changed the way the mainstream thinks and talks about BDSM. When Fifty Shades Darker, the sequel to 2015’s notorious Fifty Shades of Grey, rolled out last Friday, I checked it out in theatees, the old-fashioned way, to catch up on the saga between Christian Grey (Jamie Dornan) and Anastasia Steele (Dakota Johnson), and to offer my readers a review of the film from a sex science perspective.

To start, one important distinction we need to make is between BDSM, which is rooted in consensual role-playing, and true sadism and masochism. As I’ve mentioned before, when BDSM doms inflict pain on their subs—even when it is serious and lasting pain—it is for the purpose of pleasuring them, not causing them unwanted suffering. Sadism, on the other hand, does not involve consent.

We learn in the early moments of the film that Christian was physically abused and neglected as a child, in addition to being groomed by Kim Basinger’s Mrs. Robinson character when he was 15 years old. His mother died from a drug overdose when he was four years old and he was left alone with her body for three days before anyone found her. This trauma haunts him to this day and presumably explains his inability to have meaningful relationships with women and his preference to dominate and control them, both inside and outside the bedroom.

Although Christian does involve consent in his sexual practices with Ana this time around, at one critical point in the film, he admits to her that he is a sadist—which, as he points out, is not at all the same thing as your run-of-the-mill dominant. Furthermore, he has the revelation that he seeks out submissives—including Ana—who look like his dead mother as a way of getting back at her for the pain she caused him.

It’s crucial to point out that the belief that BDSM practitioners are psychologically disturbed is unfounded—and in fact, a recent study led by New York City-based sex therapist and author of Modern Sexuality, Dr. Michael Aaron, squarely debunks this myth. It turns out interest in BDSM is not related to having adverse or abusive childhoods, pathological personality traits or insecure (unhealthy) attachment styles, which are associated with extreme clinginess and fear of emotional intimacy.

We also meet one of Christian’s jilted ex-subs, Leila (Bella Heathcote), who led me to believe, after watching the movie’s trailer, that Fifty Shades had gone supernatural, because this woman looks nothing short of a demonic possession. After stalking Ana at her work and vandalizing her car, she breaks into her apartment and threatens her with a gun. Christian shows up just in time, subduing Leila by commanding her to “kneel” and stroking her head like a puppy. She is then hauled off to a psychiatric hospital.

BDSM scenes don’t typically extend into real life, and for arrangements that have been explicitly agreed upon to operate in this way, they don’t tend to continue on indefinitely. As well, these sorts of 24/7 D/s (dominant and submissive) relationships—also known as total power exchange relationships—are carefully negotiated with the goal of the sub’s happiness and wellbeing in mind.

The film made an interesting comment around the themes of romance and redemption; that if a man loves a woman enough, he’ll be able to give up his sexual preferences for her. As much as I’d hate to rain on viewers’ parades, based on the most up-to-date research and interviews I’ve conducted in my line of work, it’s just not possible for someone to change in this way.

A man might manage to ignore his predilections temporarily, but these interests will always be in the back of his mind, and they will be what he fantasizes about while having vanilla sex with his partner. By the end of the film, Ana accepts Christian’s marriage proposal and asks him to take her back to the Red Room of Pain. We will hopefully find out in next year’s Fifty Shades Freed whether she fully realizes what she’s signing up for.

Debra W. Soh is a sex writer and sexual neuroscientist at York University in Toronto. She has written for Harper’s, The Wall Street Journal, Scientific American, The Los Angeles Times, The Globe and Mail and many others. Follow her on Twitter: @debra_soh.