I just made this one up. Right now. But I bet someone made it up before me because it's too obvious not to have been used before. I did some web searches (with emphasis on Henny Youngman) and didn't find anything like it but I bet someone will come up with a previous similar thing:
I tried to break up with my girlfriend. Told her we shouldn't date any more. Told her adieu. So now she thinks we're married.