I put in 21 years.
3 seconds sound clip from the Mister Ed - Season 1, Ep. 5 - Stable For Three TV Series.
You can hear this line at 00:05:53 in the DVD version of the movie.
Quote context
[...]
- She's setting me up for something. I can feel it in my wallet.
- Just because a wife is nice to her husband doesn't mean she wants anything.
- How long have you been married?
- Did it ever occur to you that Kay is being nice to you because she loves you?
[...]