Princess Louise of Belgium

Princess Louise Marie Amélie of Belgium (18 February 1858 in Brussels – 1 March 1924 in Wiesbaden) was the eldest daughter of Leopold II and his wife, Marie Henriette of Austria. The Brussels thoroughfare Avenue Louise is named after her. 
First marriage and children.
Born "Louise Marie Amélie", she married her second-cousin Prince Philipp of Saxe-Coburg and Gotha in Brussels, on 4 February 1875. The bride was 17 and the groom was 31. The couple had two children:
Her father disapproved of the marriage, regarding it as an unwelcome alliance with Prussia, but her mother approved of it because Philippe lived in Hungary. 
The relationship between Louise and Philippe was not happy. Louise later wrote that she had fled the bedchamber as soon as possible the morning after her wedding, in extreme distress. Philippe is said to have been controlling, and Louise responded by living a lavish lifestyle at the court of Vienna, where she attracted much attention. 
In 1880, she suggested the marriage between her sister Stephanie and Crown Prince Rudolf of Austria.
Scandal and divorce.
In 1895, Louise, now based in Vienna, the capital of Austrian Empire, became romantically involved with Count Geza Mattachich (Mattacic, 1868–1923), stepson of Oskar Keglevich, Count of Buzin. Mattachich was a lieutenant in a Croatian regiment of the Austrian army. They met in the Prater in Vienna.
In January 1897, she scandalized Vienna by permanently leaving her husband, Prince Philippe, for Mattachich and taking her daughter with her. They traveled first to Paris, then Cannes, living in other destinations in the south of France and the rest of Europe. Her son became estranged from her, because he felt her actions had ruined his chance for inheritance. Her daughter soon left her mother at the advice of her fiancé, the Duke of Schleswig-Holstein.
In 1898, Prince Philippe and Mattachich fought a duel in Vienna, first with guns, then with swords, in which the prince was injured.
Mattachich had been arrested in Zagreb and imprisoned for four years for forgery.
Louise and Prince Philippe were finally divorced in Gotha on 15 January 1906, almost eight years after Louise had begun divorce proceedings.
Later life.
Estranged--and disinherited--from her father Leopold II, divorced from her husband, and separated from her children, Louise's extravagant expenses brought her deeper and deeper into debt. Despite being the daughter of arguably the wealthiest king of the age, she was forced to claim bankruptcy after it became known that Mattachich had forged the signature of Louise's sister, Princess Stéphanie, on promissory notes for jewelry worth about $2,500,000. As a result of this episode, in May 1898 she was interned in an asylum for six years on the orders of Austrian monarchy, which was embarrassed and scandalized by her and her husband. Mattachich was sentenced to four years in prison for forgery. Once his sentence was over, he helped Louise escape from the asylum in 1904; spied upon by emperor Franz Josef's secret service, they began life as fugitives. This predicament ended as the result of World War I and the disintegration of Austrian empire.
But before the war, when Leopold II died in 1909, the princess and her two sisters discovered that their father had left his will to his chief mistress, the French prostitute Caroline Lacroix and a portion to the Royal Trust. The sisters began a lawsuit against the Belgian state, which had made its own claims on the king's vast wealth. The outcome of the lawsuit was especially important for Louise, rather than her sisters, because she was penniless. Although she lost the legal battle, the Belgian state awarded her a sum of money, which she would only receive many years later due to the outbreak of war.
After the war, Louise and Mattacich returned to Paris, where she wrote her memoir. In it, she settles the score with various people in her life, including her father Leopold II. Yet she dedicated the work to him. Louise's memoir, "My Own Affairs", was published in 1921.
Mattacich's health deteriorated over the course of 1923 until his death that autumn. After his death, Louise moved one last time to Wiesbaden in Germany. After Mattachich's death she was given a home by Queen Elisabeth, the wife of her cousin, King Albert I of Belgium. In Wiesbaden she died on March 1, 1924. 
After her death, the royal court in Brussels went into mourning for a full month.