Season 4: Episode 71: I Take Thee, Quagmire
When Peter makes a surprise win on Wheel of Fortune, he wins a free maid for a week. While he shows off how he could cause a huge mess for her to clean up she meets Quagmire who immediately falls for her. He gives up his philandering ways and becomes a caring lover. He proposes to Joan. Peter, however, becomes irritated by the changes Quagmire made for his new fiance.