My Best Friend's Girl (2008) on Netflix

Plot summary

Tank answers phones at a call center, and on the side he hires himself out to men who have been dumped. He takes their former girlfriends on dates so dreadful that the women decide their exes were not so bad after all. Dustin, Tank's step cousin and roommate, has fallen for Alexis, a colleague at his office. He tells her he loves her on their date, and she answers that she wants to stay friends. Tank offers to take her out for nothing, and Dustin says no. Then Dustin spots Alexis flirting with another co-worker and asks Tank again, and Tank agrees. The evening goes badly on purpose, but Alexis does not seem to mind, and when Tank brings her home he will not come inside, staying loyal to Dustin.