In William Congreve's "The Way of the World”, why does Millament read Suckling and Waller in Act4?

In the play The way of the World, Millament reads verses
from Suckling andWaller in Act 4 because she is under a profound level of stress due to
her own feelings about how she connects with men, particularly, in the aspect of
intimacy. The poem that she is reciting is supposed to come from a 17th century ballad,
‘‘Ballad upon a Wedding’’, which is a satire of the conventional, super-serious
ceremonies of marriage.

Basically, Millament is a female
character who is archetypal in that she is consumed by her thoughts, and tormented by
her upbringing. She is consistently battling the ideas put upon her as a child, versus
the conclusions about men that she is beginning to develop now that she is a woman.
Hence, with a pending marriage in the future, her disdain for it, and her inner wishes
for freedom, she exists in a conundrum where she tries to find herself. The compulsive
recitation of the poem was a way to cope with her stress and
anxiety.