Monk, 38, announced the break-up in a late-night Instagram post.
“I don’t know how to explain this because it’s an unusual circumstance to be in,” she wrote.
“But because I entered this relationship so publicly, I know I owe an answer to Australia about my personal life.
“I went into this experience looking to settle down and start a family.
“I gave it the best shot I could and my intentions were everything I said I was looking for, but unfortunately it just didn’t work out.
“As much as I respect him [Laundy], we are just very different people.
“There were no contracts or pressure to stay together whatsoever from anyone and we remain friends.
“The positive in this whole experience is it taught me to jump out of my comfort zone in order to find real love and made me much stronger.
“I sincerely want to apologise to anyone who invested so much love and support and I hope I haven’t disappointed anyone.”
The news has come less than a fortnight since Monk holidayed with Laundy, 45, at the Silver Star Mountain ski resort in Canada, from where she posted several happy snaps.
https://www.instagram.com/p/BdD8XGQjeFZ/?hl=en&taken-by=sophiemonk
But the reality-TV relationship was rumoured several times to be merely a front, and that the couple had in fact broken up immediately after the The Bachelorette finale aired in October.
Monk was repeatedly forced to deal with claims that the relationship was a sham and that their public appearances were staged for the cameras.
“Every day is something different and because I travel and work all the time you can’t always be together. There will be another story that we’ve broken up as soon as I go and do another job, to be honest,” she told Nova radio late last year.
“You’ve just got to roll with it. I guess at least people are interested.”
Monk’s star turn on The Bachelorette may not have had the romantic outcome she’d hoped for, but it won her a huge legion of new fans and proved a huge boon for her career.
Her efforts on the hit show landed her the hosting role on Channel 9’s new reality show Love Island, screening this year.
Monk first came to prominence in 2000 as a contestant on the seminal reality TV singing contest Popstars, which saw her enjoy chart success as a member of the girl group Bardot.
