Lembit Opik has admitted some Liberal Democrats see him as too much of a "joker" to become party president.
The Montgomeryshire MP, one of three candidates for the post, said he used to get angry at such labels.
But Mr Opik, whose engagement to pop star Gabriela Irimia of the Cheeky Girls ended last summer, says he tries to understand that "natural caution".
In an e-mail to party members Mr Opik said he was being candid and would put himself "heart and soul" into the job.
The 43-year-old politician was previously leader of the Welsh Liberal Democrats and a frontbench spokesman on housing.
He has also appeared on television quiz shows and spoken out about the dangers of asteroids colliding with Earth.
But he is probably better known for his much publicised romances with ITV weather forecaster Sian Lloyd, whom he was with for four years, and then Miss Irimia.
The end of their engagement hit the headlines in the summer, particularly when the pop star said she had miscarried their baby
Mr Opik did not refer directly to the their break-up in his message, but wrote that 2008 had been "a very difficult year for me".
It had also seen the sudden death, a few weeks later, of his "closest friend and confidant" lecturer David Hamer , aged just 46.
In the e-mail going to all party members next week, the MP said the events "almost stalled my life" and delayed his presidential campaign, but also gave him "insight into how others see me"
"With some humility, I can tell you I've learned to see why some folk are concerned about my presidency," Mr Opik writes.
"Some fear I'll be unpredictable, a wild one, or too involved in a profile outside politics.
"Or they think I'm too much of a joker, or a political lightweight.
"Or they believe I want to be president for my own self-promotion."
He says he has previously been "frustrated and angry with people for thinking these things about me".
"But looking at it now, I realise that the right response is not to be angry, but to be a bit more empathetic to these concerns and to appreciate why some feel this way, and try to accommodate that very natural caution within my equally natural enthusiasm and effusive optimism about the human race."
Mr Opik recognised that his approach to politics was "different", but insisted it could be an "enormous asset" to the party by reaching out to people not normally interest in politics.
He said as president he would form a "great partnership of inspiration, flamboyance, courage, teamwork, warmth and affection".
Mr Opik admitted his campaign team were worried at his decision to send out the personal message.
He said he hoped party members would "appreciate my candidness in the spirit in which it's intended."
The deadline for postal ballot in the presidential election is 7 November. Entrepreneur Chandila Fernando and Lords communities spokeswoman Baroness Scott are also standing.