The New Adventures of Old Christine (2006)

S1E2 Supertramp

Upon discovering that Richard is happily involved with "new" Christine, Christine resolves to find her own romantic interests. After a series of unsuccessful encounters with potential suitors, she unexpectedly bumps into a man named Stan while shopping for groceries. What Christine doesn't realize is that Stan is actually a father at Ritchie's school, infamously referred to as "Sad Dad."