The sudden death of his son made David Cameron question his future in politics, the Tory leader admitted today in an emotional section of his conference speech about his family's loss.
When six-year-old Ivan, who had cerebral palsy and epilepsy, died in February after a lifetime of health complications it was like "the world stopped turning", he told activists in Manchester.
He said that for all the achievements the party had made since its last annual gathering, for him and his wife the devastating loss would be the only thing the period was associated with.
"For me and Samantha this year will only ever mean one thing. When such a big part of your life suddenly ends nothing else - nothing outside - matters at all.
"It's like the world has stopped turning and clocks have stopped ticking. And as they slowly start to turn again, weeks later, you ask yourself all over again: do I really want to do this.
"You think about what you really believe in; what it is that sustains you."
In a tribute to Samantha, he said: "I know what sustains me the most: she is sitting in the front row and I am proud to call her my wife."
Turning to his beliefs, he said that above all it was "the importance of family".
"That fierce sense of loyalty you feel for each other; the unconditional love you give and receive especially when things go wrong or you get it wrong; that powerful sense you have when you hold your children and there's nothing, absolutely nothing, you wouldn't do to protect them."
The couple have two other children - five-year-old Nancy and three-year-old Arthur - and Mr Cameron hinted last month that he would like to add one more to the clan.Reuse content