What is Meg's role in "The Birthday party", and how does Harold Pinter use her?

Petey's wife, Meg Boles is a good-natured woman in her sixties. If only from a lack of any reference to offspring of her own, it is implied that she and Petey are childless, thus she fills a void in her life by turning the Boles's boarding-house tenant, Stanley Webber, into a kind of surrogate child. She insists on calling him "boy" and mothering him. She even takes liberties appropriate to a parent—though not to the landlady of an adult roomer—by invading his privacy to fetch him down to breakfast.

At the same time, Meg flirts with Stanley, trying to fill a second void in her life. Her marriage to Petey has settled into mechanical routine, as their listless and inane dialogue that opens the play reveals. Meg tries to win Stanley's approval of her as a woman, shamelessly fishing for compliments. Stanley, in his mildly perverse manner, responds by teasing her, knowing that she is both vulnerable and gullible.

As the play progresses, it becomes clear that Meg, though a mental lightweight, is a decent woman. She is also rather sentimental. Although it is probably not even Stanley's real birthday, she insists that it is, determined to help Stanley weather his self-destructive despondency. She also seems to be his last hope, and her absence when he is taken away near the end of the play intensifies his final wretchedness.