Here's a bit about Charlotte's romantic life from janeaustenworld.com
"When Charlotte was sixteen, the government proposed a marriage to Prince William of Orange (1792-1849), the son of King William I of the Netherlands. It would strengthen the alliance between Great Britian and the Netherlands and get the rebellious Charlotte off the Regent's hands so he favored the marriage. Charlotte, at first, acquiesced and the engagement was announced after their meeting at a dinner at Carlton House on December 11, 1813. While she was spinning out the negotiations with the Prince of Orange, the allied sovereigns arrived in London in June 1814 to celebrate their victory over Napoleon. Among them, in the suite of the Emperor of Russia, was the young and handsome Prince Leopold of Saxe-Coburg. He made several attempts to attract the notice of the Princess, but she, with her heart elsewhere, paid very little attention. She had already met Prince Frederick, the King of Prussia's 19 year old nephew, at a dinner party at Carlton House and fallen in love with him. She determined to break off the engagement. Charlotte announced on June 16th,1814 that she would have none of the Prince of Orange. This was hardly surprising as his looks had earned him the nickname of 'the Young Frog.' This was not Charlotte's first love affair, for she had previously carried on a clandestine correspondence with Captain Hess, a handsome officer of the 18th Light Dragoons. Lady de Clifford, Princess Charlotte's governess, had allowed Hess who was reputed to be an illegitimate son of the Duke of York and therefore a cousin to often ride beside Charlotte's open carriage in the autumn of 1812. Miss Cornelia Knight, one of Charlotte's ladies, helped her meet Prince Frederick privately at Warwick House during his June 1814 visit to London. Next month, July 1814, the Prince Regent, heard rumors that his daughter was having secret meetings with a man. He didn't find out about Frederick but thought it was his disreputable 35 year old cousin Prince Augustus of Prussia. The Prince Regent suddenly appeared upon the scene and, after dismissing her Warwick household, sentenced Princess Charlotte to a strict seclusion in Windsor Park. "God Almighty grant me patience!" she exclaimed, falling on her knees in an agony of agitation: then she jumped up, ran down the backstairs and out into the street, hailed a passing cab, and drove to her mother's house in Connaught Place. She was discovered, pursued, and at length, yielding to the persuasions of her uncles, the dukes of York and Sussex, of Brougham, and of the Bishop of Salisbury, she returned to Carlton House at two o'clock in the morning. She was immured at Cranbourne Lodge in Windsor Great Park, but no more was heard of the Prince of Orange. In spite of the watch kept on her, Charlotte managed to carry on a secret correspondence with Frederick until he returned her portrait and broke off their relationship in January 1815. The way was at last open to Prince Leopold of Saxe-Coburg. "