I can't remember, but now that the question has been brought up, it is the burning question on my mind.
I might just have to watch all 3 movies tomorrow to find the answer
I'm pretty certain he does NOT say that. I watched all three repeatedly this summer for a research paper I was working on, and I would have noticed that line (despite distractions, lol).
Edited to add: did you watch until the end of the credits of POTC3? They do meet again then...
The only place I think he could have said it is on POTC 2 where he is talking to her through the cell bars. He tells her he will come back and marry her, if she will have him. She says if it weren't for these bars she'd have him already. Then dear old dad breaks the candle holder. Then Will says, "Keep a weather eye out." And leaves.
We watch the movies all the time. We know pretty much all the lines. We went to a friend's for dinner after they moved into a new place. They didn't have the sound system hooked up correctly, but they had the movies on anyway. We'd watch and say the lines! Great fun!