Three's Company (1977)

S3E20 An Anniversary Surprise

Title: A Surprise for the Anniversary Plot: Helen suspects that Stanley is abandoning her for another woman. Unbeknownst to her, the "other woman" is merely a real estate agent who has helped him secure a fantastic new home in Chevroit Hills. When Stanley reveals to Helen that they’ve sold their current building and are heading to their new place, he also hints at the exciting prospects ahead, including a potential spin-off of their lives together.