Country sweethearts Brantley Gilbert and Jana Kramer have called it quits.

According to someone in the know, Brantley and Jana blame their careers for the break-up. The insider told People magazine,

They are both so busy right now. They are both on the road and have to spend a lot of time apart, which isn't ideal for any couple, let alone a couple trying to plan a wedding."

The source also says that Brantley and Jana were happy together, but know the split is for the best.