So I just happened to see his American Express bill.
5 seconds sound clip from the When Harry Met Sally... movie soundboard.
You can hear this line at 00:28:35 in the Blu-ray version of the movie.
Quote context
[...]
- Marriages don't break up on account of infidelity, it's just a symptom that something else is wrong.
- Oh, really? Well, that symptom is fucking my wife!
- So I just happened to see his American Express bill.
- What do you mean just happened to see it?
- Well, he was shaving, and there it was in his briefcase.
- What if he came out and saw you looking through his briefcase?
- You're missing the point. I'm telling you what I found.
- He just spent 120 dollars on a new nightgown for his wife.
[...]