A joke which makes some sense

I Want To Live Forever!

A man goes to the doctor and says, "Doc, I would like to live very long. What should I do?"
"I think that is a wise decision," the doctor replies. "Let's see, do you smoke?"
"Oh.. Half a pack a day."
"Starting NOW, no more smoking." The man agrees. The doctor then asks, "Do you drink?"
"Oh, well Doc, not much, just a bit of wine with my meals, and a beer or two every once in a while."
"Starting now, you drink only water. No exceptions." The man is a bit upset, but also agrees. The doctor asks, "How do you eat?"
"Oh, well, you know, Doc, normal stuff."
"Starting now you are going on a very strict diet: you are going to eat only raw vegetables, with no dressing, and non-fat cottage cheese."
The man is now really worried. "Doc, is all this really necessary?"
"Do you want to live long?"
"Yes."
"Absolutely necessary. And don't even think of breaking the diet." The man is quite restless, but the doctor continues, "Do you have sex?"
"Yeah, once a week or so..., only with my wife!" he adds hurriedly.
"As soon as you get out of here you are going to buy twin beds. No more sex for you. None."
The man is appalled. "Doc... Are you sure I'm going to live longer this way?"
"I have no idea, but whatever you live, I assure you is going to seem like an eternity!"