Sources close to the couple have said, according to reports, that the pair had agreed to try to work past the scandal and to try to save their two-year relationship.
However, the initial report last week indicated Seebohm then learned new information about the alleged affair and announced the following day that her relationship with Larkin was over.
"I would like to take this opportunity before more speculation and rumours are spread," she wrote on her Instagram page.
"Due to current events that have occurred, Mitch Larkin and I have decided to end our relationship."
The situation has turned even messier with reports surfacing Larkin is upset that the circumstances behind their separation have been publicly reported.
Seebohm on Sunday night offered another insight into the bitterness within the breakup with a scathing dig at Larkin which included a warning about the six-time Commonwealth Games gold medallist.
She posted a photo on her Instagram story which said: "Something I learned about people... if they do it once, they'll do it again".
Seebohm, a seven-time Commonwealth Games gold medallist, then posted another cryptic warning on Twitter, interpreted by many fans as another swipe at Larkin — and his reported anger at their breakup becoming public knowledge.
Seebohm last week also posted another image of herself performing acrobatic moves around a pole dancing pole.
"This is the only bender I go on these days @purepoleacademy #purepole," Seebohm captioned the image.
She also told a fan on Instagram last Thursday: "It's been a hard month for me but I'm doing my best."
The Courier-Mail reported last week Seebohm and former backstroke competitor Meagen Nay, who also previously dated Larkin, shared messages on social media.
"There is hard evidence in here, trust me," Nay posted on social media.
Nay and Seebohm also made identical posts to their Instagram stories, each posting the same image of a seascape with the quote "What is coming is better than what is gone".
Seebohm posted another image on Instagram last week with a message that appeared to be about Larkin.
"The sad thing is, I actually thought you were different," she wrote.
The breakup came in the same week the former couple posed together in an advertising promotion for Brisbane's ICON fashion series at Brisbane's Treasury Casino and then took part in the fashion show.
Seebohm missed the start of the Australian swim team's training camp in Cairns last week, but declared her decision to skip the camp had nothing to do with her breakup.
Larkin also pulled out of the Citizens of the Great Barrier Reef expedition last week — a program designed to raise awareness for the health of the reef.
Aussie swim coach Jacco Verhaeren admitted last week Seebohm's absence was "not ideal".
"It is of course always unfortunate if somebody has to miss out on the opportunity to be here and be with her teammates and train together," he said.
"It is difficult but of course she can train at home as well."
He also insisted the breakup will not cause a rift in the Aussie team.
"Of course, it is never nice to be in this situation but it is part of life. They're both mature people," he said.
"It's very unfortunate, very sad but at same time life moves on. They're very young and I'm sure they will too."
