It was for a long time. I know that Chaplin him self like women younger than him. I think all of them except for one were over 18 when he married them.

President John Tyler actually married a woman who was in her 20's and he was some where in his 60's. They had children, and actually two grandsons's of his are still living right now which is really crazy to think about. Tyler him self was living when Washington was President.

http://nymag.com/daily/intelligencer/2012/01/president-tyler-grandson-alive.html