Queen Elizabeth II's younger sister, Princess Margaret, was one of the most controversial members of the royal family. From her tumultuous marriage, steamy affairs, and wild parties, she never failed to make headlines.

She met her match in her husband, Antony "Tony" Armstrong-Jones, best known as Lord Snowdon, and they both became subjects of numerous controversies and rumors even before their wedding.

Here are 7 wild but true facts about the complicated relationship Princess Margaret and Lord Snowdon had:

1. He was the first commoner in 400 years to marry a royal

Armstrong-Jones, was the son of a senior lawyer and a socialite, who took up a career as a photographer. After meeting and falling in love with the Queen's sister, Princess Margaret, he proposed to her at a "safe house" that belonged to his friends, Camilla and Jeremy Fry. A year after their marriage, he became the 1st Earl of Snowdon, also commonly known as Lord Snowdon, a title given to him by the Queen.

2. Jones-Armstrong was not Margaret's rebound

Contrary to popular belief, Princess Margaret no longer had feelings for Peter Townsend before marrying Armstrong-Jones. According to her biographer, Christopher Warwick, the claims that the princess wasn't over her former flame is "utter nonsense." When he asked her about it, she replied, "I married Tony five years after the end of Peter Townsend."

3.  Armstrong-Jones fathered an illegitimate child before their wedding

A few years ago, a woman named Polly Fry came forward with the claim that Armstrong-Jones was her father. Polly, who was born just a few weeks after the royal wedding in 1960, was the result of an affair Armstrong-Jones had with Camilla Fry. She took a DNA test in 2004 to prove paternity.

"Although we may like to think of our own generation as being wild and wonderful, in comparison to what our parents got up to in the swinging 60s we are mere innocents caught up in the aftermath of the postwar free-love era," Polly wrote in a 2008 article for the Daily Mail.

There are even more scandalous facts about the royal couple...

4. The princess was convinced her husband was queer

Besides his complicated relationship with his wife, there were rumors that the Lord Snowdon was bisexual. A close friend of his said, "if it moves, he'll have it," and according to "most of the girls" he worked with at the studio, "there seemed little doubt that Tony was gay." When asked to clarify, Armstrong-Jones once said, "I didn't fall in love with boys, but a few men have been in love with me."

Princess Margaret later shared her thoughts about her husband's sexual orientation with her biographer. She said, "I enjoyed his company very much, but I didn't take a lot of notice of him because I thought he was queer."

5. They were both unfaithful

Although it's no secret that their marriage was a mess, what many people don't know is the fact that Armstrong-Jones wasn't the only one caught up in extramarital affairs. According to The Evening Standard, Margaret allegedly had a "brief fling" with her husband's former schoolmate, Anthony Barton, while Armstrong-Jones "indulged in a series of casual liaisons."

Armstrong-Jones was then rumored to have been involved in a "serious affair" with Jacqueline Rufus-Isaacs right around the time that the princess was having a "brief but passionate liaisaon" with nightclub pianist Robin Douglas-Home.

However, none of these relationships caused as much frenzy as the princess's affair with Roddy Llewllyn, who was 17 years her junior. They were caught vacationing together on a Caribbean island, and that was the beginning of the end of Margaret and Lord Snowdon's marriage.

6. They were the first royal couple since 1901 to divorce

After 18 years of marriage, Princess Margaret and Lord Snowdon parted ways in 1978, making them the first royal couple in decades to divorce. Although she was romantically linked with a few other men, Margaret never remarried. Armstrong-Jones on the other hand, wed Lucy-Lindsay-Hogg the same year his marriage to the princess ended.

7. They remained friends until Margaret's death

Despite their tumultuous marriage, Margaret and Armstrong-Jones remained close until she died in 2002. Armstrong-Jones continued to take the royal family's official portraits even after their divorce and took part in royal activities. He passed away in January 2017 at the age of 86.

Her marriage is a stark contrast from the relationship her sister has with Prince Philip. The Queen and the Duke of Edinburgh just celebrated their 70th wedding anniversary, and despite rumors that he cheated, they still remain together.