Media had reported that the pair were preparing to get married in February, and Min Hyo Rin's label has confirmed the news! The two are making wedding preparations for February. Her label said, "It's true they're getting married. They haven't set a date yet, but they are preparing quietly."
According to an insider, the two will not have a big fancy wedding, but a small one. They started dating back in May 2015.
Congratulations to the two!
[UPDATE: YG Entertainment has also confirmed the news, saying, "It's true that Taeyang and Min Hyo Rin will get married in February. They'll be having their wedding before he enlists."]