Your uncle, an adulterer.
5 seconds sound clip from the The Pit and the Pendulum (1961) movie soundboard.
You can hear this line at 01:05:11 in the Blu-ray version of the movie.
Quote context
[...]
- And now, my dear Nicholas, I have you exactly as I want you... helpless.
- Is it not ironical, my husband?
- Your closest friend, an adulterer.
- Do you not find that amusing, dear Nicholas?
- Happening? Why, what should be happening, Isabella?
[...]