US President Barack Obama said he stopped smoking out of fear of his wife.

While CNN was recording a tape, Obama was standing up after the event and asking the man next to him if he had given up smoking, but the man returned the question to him.
When the question was returned to him, Obama with a smile on his lips, said: "I haven't had a cigarette in probably six years. That's because
I'm scared of my wife."

Obama who included in his memoir 'Dreams from My Father' how he was a smoker in his youth.

In his first year in office, Obama described himself as "95 percent cured" from smoking but admitted he has occasionally "fallen off the wagon" in his efforts.

In December 2010, then White House spokesman Robert Gibbs said that Obama had not smoked for nine months and had been "stubborn" in trying to quit, despite the stress of the job.

In February 2011, First Lady Michelle Obama who is a campaigner for public health said that the president had not smoked for a year and that she was not giving him a hard time about the issue.

"When somebody's doing the right thing, you don't mess with them," she said.

Well i think love also plays a major role in this.

http://www.tutubranch.com/2013/09/why-Obama-stopped-smoking.html