Seymour assures Audrey, "Suddenly, Seymour/Is here to provide you/Sweet understanding/Seymour's your friend." Then at the end of the song, Audrey proclaims, "Seymour's my man!" At least in the movie, Seymour and Audrey perform a Big Damn Kiss after this.
Throughout the film, Seymour is convinced that Audrey would never go with a guy like him; especially without money. Cue Audrey admitting to him near the end that she fell for him ever since she started working at the shop.
"And if I'm in the plant, then I'm part of the plant, so, in a way, we'll always be together..." That entire scene is both a Heartwarming Moment and a Tear Jerker.
While Audrey refuses to dump Orin, in spite of the fact that he hits her and insults her frequently, Seymour, Chiffon, Ronette, Crystal, and even Mr. Mushnik all urge her to drop that abusive prick and find a man that's worth her time. Audrey may think she's useless, but the people around her know she deserves so much more than life has given her.
There's also a nice little moment in the stage show when Orin first shows up to pick up Audrey — who, by now, has shown up to work with a black eye and a broken arm thanks to him. Ronette, Chiffon and Crystal all tell Orin that they know all about what he did to Audrey, and they don't approve, and tell him in no uncertain terms to get lost. Granted, it doesn't work, but it was nice of them to try. (In at least one production, one of the girls tries to physically attack Orin, only to be held back by the other two — not that he notices, of course.)
Seymour and Audrey getting their happy ending in the film version.