It’s not at all uncommon to see book authors make a quick cameo in the movie adaptation of their work, and “It Ends With Us” follows in that grand tradition. It’s a quick moment, but yes, author Colleen Hoover can be spotted on screen.

Adapted from Hoover’s 2016 book of the same name, “It Ends With Us” tells the story of Lily Bloom (Blake Lively), a florist who’s just opened her own flower shop in Boston. When she meets handsome neurosurgeon Ryle, sparks quickly start flying.

But, as their relationship develops, it becomes clear that Ryle is abusive — a stark realization for Lily, whose own mother was abused by her father. Lily is determined to believe it’s not the same situation though, desperately clinging to the idea that her injuries at Ryle’s hands were accidents, and that he’s not actually abusing her.

Things don...