Jenelle Evans and fiance Nathan Griffith enjoyed time in St. Thomas last week. The 23-year-old "Teen Mom 2" star posted a series of photos from the vacation on Instagram. Evans appears in a bikini in several of the pictures, just over six months after giving birth to her second son, Kaiser. Evans and Griffith were in the tropical locale for a week, and got engaged Jan. 6. The couple have been together since April 2013, and welcomed Kaiser in June 2014. Evans came to fame on the second season of MTV reality series "16 & Pregnant," and subsequently appeared on five seasons of "Teen Mom 2." The reality star is also mother to 5-year-old son Jace with ex-boyfriend Andrew Lewis, and will return for a sixth season of "Teen Mom 2" in 2016.