"She didn't think Booka would be the kind of girl to do that to her," says the source.
"Even though Jake and Booka knew each other before the show, Bec was reassured by both of them it was just a professional relationship.
"She feels really betrayed."
On Tuesday, Bec also hinted at a potential feud with Booka to Nova radio duo Fitzy and Wippa when she coyly remarked that she "might have" seen the kiss video.
“So this is after the experiment right? This wasn’t while you were doing it was it?” host Ryan 'Fitzy' Fitzgerald asked.
Bec replied: “No this was after the experiment had finished.. and Jake and I may or may not have been together..”
Eagle-eyed fans have suspected that Booka and Brett are no longer together ever since the two didn't watch their wedding episode together.
Reality TV podcast So Dramatic! host Megan Pustetto later shared: "I can confirm that these two are no longer together, and not only that, they don't even make it to the final vows.
"A person who knows Brett got in touch and said: 'I know Brett, they definitely do not last. He reckons he's going to get a bad edit, he's back in Geelong and telling people they are not together.'"
Musician Booka also dropped her band Internet Friends' new single, Beam me up soft/f***boi and though it only lasts for a minute, fans reckon it's all about her groom Brett doing her wrong.
Lyrics include the lines: “Boy, there’s some bulls*** on your face I’m coming,” and "You’re so predictable and you’ve lost all your appeal. You’re so basic my hymen has gone resealed." Plus, the guy in the video could be Brett's twin.
We’re unpacking all the relationship, sex and dating woes of this season’s Married At First Sight stars in our juicy new podcast, Love In Reality. Listen, like and subscribe below!