After announcing the engagement of Prince Johan Friso with Mabel in June 2003, Prime Minister Jan Peter Balkenende wrote in a letter to parliament that she had given "incomplete and incorrect information" about the duration and extent of her contacts with known drug lord, Klaas Bruinsma, and that because of this, the government had decided not to seek permission for the marriage from parliament. In a letter to the Prime Minister, Friso stated that the couple had given some incomplete information, but hadn't given any incorrect information nor did they lie. The couple admitted that the sailing friendship with Bruinsma was indeed closer than had been mentioned, but denied a love or sexual relationship.
According to Dutch law, the government had to submit the couple's marriage request to parliament for its approval, a prerequisite for succession to the throne. Prince Friso said he would marry her regardless, and as a result lost his right to become king. He had been second in the order of succession, after his older brother, the then Prince Willem-Alexander.
The couple finally married in Delft on April 24th 2004. Since her marriage, Mabel has used the style of Royal Highness and the courtesy titles of Princess of Orange-Nassau, Countess of Orange-Nassau, Mrs. Van Amsberg. She was not legally created a princess, but it is customary for wives and widows of members of the royal family to take the titles of their husbands.
They have two daughter together :
1. Countess Emma Luana Ninette Sophie of Orange-Nassau, Jonkvrouwe van Amsberg/ Countess Luana born on March 26th 2005.
2. Countess Joanna Zaria Nicoline Milou of Orange-Nassau/Countess Zaria born on June 18th 2006.
It was decided that their children each would receive the titles of Count/Countess of Orange-Nassau and Jonkheer/Jonkvrouw van Amsberg. Because he did not ask the Dutch parliament for permission to marry, Prince Friso ceased being a member of the royal house and their children didn't included in the line of succession