Georgiana may have been an important presence in the nuptials of Maria Fitzherbert and the Prince of Wales but that didn't leave a warm place for her in Maria's heart. For so beloved a duchess, there were three distinct hate-ahs of Georgiana: Jane Duchess of Gordon; her sister in law, Lavinia Countess Spencer, and Mrs. Fitzherbert.
Georgiana just didn't care for Maria's personality and when she found out the socialite's feelings about her, she decided she didn't much like Georgiana either. Truth is, she was probably just jealous of Georgiana and her celebrity lifestyle.
Tea times Maria shared with Mrs. Eleanor Creevy tended to become slightly awkward because they usually culminated with Maria going into tirades against Georgiana. Finding out about her illegitimate daughter, Eliza Courtney was like striking gold for Mrs. Fitzherbert. She proudly boasted the fact to Mrs. Creevy over tea, hoping the words would make it to the venomous tongues of gossipers. It didn't really catch on. Maria's jealousy didn't hinder up until Georgiana's final years; she was still bitching about her in 1805. Mrs. Creevy would go on to quote Maria as saying she knew all the dirt on the duchess because she would read all of her husband's letters. She slyly added as she slowly stirred her tea that the Prince knew everything about Georgiana.
Apparently not enough to ruin Georgiana though! Mrs Fitzherbert's gossip left Georgiana unscathed and she never seemed to pay any mind to the threats of her good friend's jealous wife. Georgiana gracefully avoiding the barbs while at the same time getting her vengeance on Maria: she paid no attention to her.