The Wedding Singer (1998) on Netflix

Robby is stood up at the altar by Linda, who decides that the prospect of marrying a guy who sings at wedding receptions doesn't equal the attraction she felt when he was lead singer in a rock band. Robby finds consolation in his friendship with Julia, a waitress at the wedding receptions and bar mitzvahs where he performs. Julia asks Robby to help her plan her upcoming wedding to Glenn, who isn't interested in the details of the ceremony. Robby learns that Glenn also isn't totally interested in Julia and is marrying her because she "deserves it" after sticking with him for years and because he knows she's not marrying him for his money, since she dated him back before he started pulling down the big bucks.