The ERA heard conflicting evidence about the alleged affair.
Ms Latham claimed it was why she was sacked, but Malcove's owner, Alan Pilbrow, submitted he had no knowledge of her personal circumstances, and her employment ended by mutual agreement.
He had called her into his office to discuss unauthorised purchases, not to terminate her employment.
Mr Pilbrow said it was at that meeting that Ms Latham raised the alleged affair, and said one of them had to go and it had to be her.
The ERA found the evidence did not support the company dismissing her because of an alleged affair. However, it found there was no mutual agreement to end Ms Latham's employment and her dismissal was unjustified.
Ms Latham sought lost wages, but the ERA did not order an award because the company had already paid out four weeks' pay.
She also sought $15,000 compensation for hurt and humiliation. The ERA agreed a $5000 payment would be appropriate, but scrapped compensation altogether because Ms Latham's actions had contributed to the situation.
Those actions included the purchase of more than $2200 in goods without authorisation, and failing to pay for the goods until later.
The ERA noted she had also colluded with another employee to access internal emails, deleted information from the company's computers, and gave prescription drugs to another employee who was under the influence of drugs.