There’s a reason romantic fairy tales end with the wedding, assuring us that the couple lived happily ever after but not taking on the difficult task of showing us what that looks like. Very few movies attempt to show what happens after love is declared and the wedding cake has been served to the guests, when the couple has to figure out how to hold onto the stardust while sharing the grubbier and surprisingly controversial tasks of operating a household and, for many, raising children.

“The Roses,” like the 1989 Michael Douglas and Kathleen Turner “War of the Roses,” is based on a book by Warren Adler. Gone Girl author Gillian Flynn calls that book “Terrifying, black-humored, black-hearted and bristling,” a description many people might apply to her own work. The book and the two movies are about a once-loving marriage that curdles into scabrous loathing.

This lightly adapted version, changing some details but retaining the vitriol, stars Benedict Cumberbatch as Theo, an architect, and Olivia Colman as Ivy, a chef. The movie opens in a disastrous session with a counselor, as the couple tries to come up with what they love about each other but cannot resist the temptation to insult each other as viciously as possible instead. The counselor tells them there may not be a way to move forward and we get a glimpse of the underlying connection between them. They cannot help laughing at the brutality of the insults. You know the song lyric, “too hot not to cool down?” This is “too hot to ever get irretrievably icy.”

We go back in time to see their meeting in London, both of them unhappy because their ideas are not appreciated by their employers. Their immediate attracting is electric and speaking of too hot not to cool down, minutes after meeting they are having sex in the refrigerator closet.

A few years later, they are in California, parents of twins. Theo is excited about the unveiling of his dream project, a maritime museum and Ivy enjoys her barely-breaking-even crab restaurant near the water. They disagree about some parenting choices; Ivy loves to give them sugary treats and Theo is all about eating healthy and working out. But they are endearingly supportive of one another.

And then, their fortunes turn upside down. Theo’s building collapses, along with his future in the profession, the same night Ivy’s 30 covers a day restaurant instantly becomes impossible to get a reservation following one rave review. Ivy takes over as breadwinner, and Theo takes over as full-time dad, housekeeper, and physical trainer for the twins, who are as into it as he is. This is when Theo and Ivy begin to resent and then feel like they loathe each other. They separate

Colman and Cumberbatch are so endlessly watchable that it’s almost easy to overlook that this is essentially a one-joke movie, the same one over and over as Ivy and Noah get increasingly more frustrated and hurt and lash out in increasingly more lacerating ways. Comedy often comes from seeing someone burn bridges we do not dare to. The brilliant supporting cast is woefully underused, except for Allison Janney, transcending the limits of the script as Ivy’s divorce lawyer, and it just gets exhausting. The ending tries to have it both ways, likely to leave audiences saying, “Wait, what?” On the way there, depending on your tolerance for people saying terrible things to their spouses, you may find it funny.

Parents should know that this movie includes very crude and graphic language and sexual references, extreme insults and pranks, and drinking, drunkenness, and drug use. While presented in a heightened comic tone, the underlying hostility may disturb some audience members.

Family discussion: Did you find yourself taking sides over the course of the film? Whose side? Did you switch sides?

If you like this, try; “The War of the Roses” and the book by Warren Adler and, for a more dramatic and romantic look at marital discord over the years, “Two for the Road”