Usually, all this ends very badly. Constant nervous tension and frustration drive him to psychosis and a nervous breakdown. Unable to break up with her due to weak willpower, he starts drinking and beating his partner. Due to alcoholism, he loses his job. She, because of the specifics of her workplace, gradually turns into an ordinary prostitute, and her bosses, having had their fun with her, throw her out onto the street, where she becomes a drug addict and sells herself to anyone for a fix.
Well, or you'll have to make an effort to make another outcome seem believable.