Arranging to meet a woman on a sugar baby website was a “dumb mistake”, Andrew Broad has said, while lamenting that his time in politics had “made me not as nice a person”.

But the National party MP said that not wanting to become a “half laughing-stock” figure like Barnaby Joyce helped spur his decision to quit at the next election, reasoning he could have survived another campaign, despite the scandal, buffeted by the 21% margin in his Victorian seat of Mallee.

In an interview with his local paper, the Sunraysia Daily, Broad reflected on his regrets, but maintained that his biggest transgression was having dinner with a woman who was not his wife.

“I probably could have toughed it out and let the storm blow over, stepped back from the ministry and maybe could have won the seat,” he told the paper.

“But for what?”

Broad was the first Nationals MP to break ranks and condemn Joyce for his affair with a staffer early last year, but was left red-faced after a woman went public with suggestive text messages he had sent her after arranging to meet her on a sugar baby website, while he was in Hong Kong for a fruit conference.

After single-handedly destroying the use of the word “g’day”, Broad stepped down from the ministry, and then announced he was walking away from parliament, after the Herald Sun published allegations that at least three other women had complained to the National party about his behaviour.

Broad said the pressures of the job, and his large electorate, had taken their toll.

“I think I’d be lucky to have spent 10 weeks at home last year. That’s no excuse for meeting someone who wasn’t my wife and having dinner with her,” he said.

“The job does have huge effects on family life.”

Broad’s vacancy opens up one of the Nationals’ blue-ribbon seats for the first time in six years, although it is expected to come under threat from an independent candidate, following a trend of challenges to the Liberals’ coalition partner in recent years.

The party’s preselection opens on Friday, and the candidate will be chosen on 19 January.

The Nationals deputy leader, Bridget McKenzie, has decided against throwing her hat in the ring, after failing to find internal support. McKenzie is still eyeing the seat of Indi, held by the independent Cathy McGowan, for a potential lower house move.

After a horror year, the National party wants a woman to win the preselection, to help deflect from its “boy’s club” reputation.

Attempts by the party leader, Michael McCormack, to point to the fact that “both” female National MPs were ministers have so far failed to shift public perceptions.