Twain tied the knot with Frederic Thiebaud, two years after splitting with her husband of 14 years Robert Lange -- who allegedly had an affair with Thiebaud's then wife.
The couple announced their engagement last month, and chose a romantic island location to exchange vows hours after seeing in 2011.
"They were married at sunset in Rincon, Puerto Rico, in front of 40 of their closest family and friends," Twain's manager Jason Owen told said in a statement to cited on the Canadian-born singer's website.
Celebrity bible People magazine reported that the pair became romantically involved in 2009, finding solace after their respective spouses allegedly had an affair which broke up both marriages.
In a letter to fans in December, Twain wrote: "In the last two and a half years of adjusting to life after separation and divorce, I needed to lean on others more often than I was accustomed to.
"I am excited to share some personal news with you: I'm in love!" she said, adding that Thiebaud was "a compassionate, understanding friend and over time, an amazing love has blossomed from this precious friendship."
Twain and music producer Lange had married in 1993, six months after meeting. Living between homes in New Zealand and Switzerland, the couple had a son who was six when they separated.
