Too Much Sex

I couldn't help but overhear two guys in their mid-twenties while sitting at a bar. 

One of the guys says to his buddy, "Man you look tired."

His buddy says, "Dude I'm exhausted. My girlfriend and I have sex all the time. I just don't know what to do." 

A fellow about my age (70), sitting a couple of stools  down had also overheard the conversation. He looked over at the two young men and with the wisdom of years says, 

"Marry her. That'll put a stop to all that rubbish!"