As a rule, the answer is...No. Of course, there are exceptions and you may even be able to name a couple or two in real life who have managed to maintain a happy, long-term relationship. But please trust me when I say this: THESE ARE THE EXCEPTIONS.
I'm 38 years old, and I can assure you that the ways that I spend my Friday evenings at this point in my life, for example, are pretty damn different from how I spent them when I was, say, 25 years old. To give you a full picture, as I write this, I've got one of my dogs seated on the couch next to me and a fire that's burning in my living room fireplace. When I was 25? Child, please. I can assure you that I was somewehere that was loud, packed with people, and brimming with all the energy that comes with having the rest of your life ahead of you.
When it comes to a couple, such as Demi Moore and Ashton Kutcher, I'm hard-pressed to believe that there aren't major differences in the ways that a 49 year old and a 33 year old choose to spend their time, or the kinds of energy levels they have. A difference of 16 years? Come on, let's everyone be honest.
Sure, it can work for a very rare few, but I wouldn't recommend such an enormous age difference for anyone looking for lasting love.