The biggest change to Brian (played by DB Woodside) in the "Perfect Find" movie is, well, he's Black, compared to the "tall white guy" Jenna fell hopelessly in love with in Williams's book before meeting Eric. It was a purposeful decision on Perrier's part, who's been vocal about the movie having an all-Black cast.
But more notably, Brian doesn't make too many appearances in the film, unlike the book. In fact, Woodside's Brian only shows up in one pivotal scene with Jenna to break the news that his mom died and he wants Jenna back. In the book, however, the former couple's reunion is much more emotional, as Jenna ventures back to the home the two used to live in together. They even go out on a date (while Jenna is still seeing Eric), which gets cut short when Jenna realizes she's completely over the heartbreak of her ex and wants nothing to do with him.
