Royal Wedding: Drunk and Bigamous

Before he became King George IV, George the Prince of Wales (1762 –1830) fell in love with the twice widowed, Maria Fitzherbert and they secretly married. The prince continued, however, to enjoy a luxurious and exorbitant lifestyle and he soon plunged into great debt.
George, Prince of Wales (1738-1820) 
Luckily, the truth of the prince's marriage was not known by the public, as it would have caused an immense scandal. But parliament did grant the prince £161,000 (equivalent to £18,450,000 today) to pay his debts.
Maria Anne Fitzherbert by Thomas Gainsborough, 1784
The prince continued to spend and his debts continued to escalate. Things became dire, but the prince's father, the king, would only assist his son, the prince, if he would marry his cousin, Princess Caroline of Brunswick.

And so, the wedding was duly arranged and Princess Caroline arrived so richly dressed that she could hardly walk. The prince, however, arrived for his wedding day extremely drunk. The Prince of Wales then proceeded to become even more drunk, which meant that he spent his wedding night passed-out, in front of the fireplace, on the bedroom floor. In the early morning, the Prince managed to perform his conjugal duties, with the result that a daughter was born nine months later.

As to the Prince's marriage to Maria Fitzherbert, it was declared technically illegal, because he was the heir to the throne and she was Catholic.