"It was a very hard situation but trying to handle it with grace," she wrote, adding a love heart emoji.
In May, Wilson teased that she was "happily" in a relationship but did not reveal the identity of her partner.
Then last week, she made her relationship Instagram official: "I thought I was searching for a Disney Prince … but maybe what I really needed all this time was a Disney Princess," the Pitch Perfect actor wrote in a caption of a selfie with Ramona.
Afterwards, in an opinion piece, Sydney Morning Herald columnist Andrew Hornery wrote that he had given Wilson two days to comment on her relationship, describing it as a "big mistake".
"It was an abundance of caution and respect that this media outlet emailed Rebel Wilson's representatives on Thursday morning, giving her two days to comment on her new relationship with another woman, LA leisure wear designer Ramona Agruma, before publishing a single word," he wrote.
"Big mistake. Wilson opted to gazump the story, posting about her new 'Disney Princess' on Instagram early Friday morning, the same platform she had previously used to brag about her handsome ex-boyfriend, wealthy American beer baron Jacob Busch."
Hornery added in his column that Rebel had her "bestie", the actor Hugh Sheridan, doing radio interviews on breakfast FM on Friday morning, during which he gloated about introducing the women to each other six months ago.
"Apparently they had hit it off pretty much immediately, but had kept the relationship under wrap," he said.
"Considering how bitterly Wilson had complained about poor journalism standards when she successfully sued Woman's Day for defamation, her choice to ignore our discreet, genuine and honest queries was, in our view, underwhelming."
The newspaper's editor Bevan Shields has since published a note offering "transparency" on what happened.
"Our weekly Private Sydney celebrity column last week asked Wilson if she wished to comment about her new partner. We would have asked the same questions had Wilson's new partner been a man," he wrote.
"To say that the Herald 'outed' Wilson is wrong.
"Like other mastheads do every day, we simply asked questions and as standard practice included a deadline for a response. I had made no decision about whether or what to publish, and the Herald's decision about what to do would have been informed by any response Wilson supplied.
"Private Sydney is a column in which the writer's interaction with his subjects is often part of the story. Saturday's piece followed that theme in giving readers insights into our interaction with Wilson and her PR team. This was not a standard news story."
Shields signed off by wishing the couple well.
Social media users were quick to come to the defence of Wilson, slamming the Sydney Morning Herald piece.
BBC reporter Megha Mohan wrote on Twitter, "I've just read this @smh piece 3 times to make sure that I wasn't misreading. The publication messaged Rebel Wilson saying they would out her in 2 days - and is now complaining that she chose to announce her relationship with a woman herself. Quite astonishing."
Another woman wrote, "Sydney Morning Herald issuing a think piece on how they gave Rebel Wilson 48 hours before outing her to the world, but *she* is the bad person for using that time to come out on her terms has left me flummoxed. What a thing to do, let alone admit to, let alone expect pity for."
Another person posted: "When I saw 'the Sydney Morning Herald threatened to out Rebel Wilson and then complained that she scooped them' I thought someone had leaked an email or something. It never occurred to me that they would publish this narrative of the events in print and expect it go to well."
