"Thanks to everyone for all the support through a very difficult time!" The former backup dancer, 28, posted earlier this afternoon.
His last Tweet was March 18: "I love my wife!!!"
Earlier, a source told Us the duo -- who wed in 2002 when Rimes was just 19 -- "have been separated for a while."
"They are leading separate lives and not staying together most of the time, but still in each other's lives as best friends," the source said. "They are still not divorcing yet, but are working through things and taking time apart -- as they have been -- while they figure things out."
A rep for Rimes had no comment.
The current issue of Us Weekly reports Rimes is still having an affair with her Lifetime movie costar Eddie Cibrian. His wife, model Brandi Glanville, left him as a result.
"Eddie and I have decided to take some time apart," says Glanville, mother of Mason, 6, and Jake, 2. "I want to do what is best for our children. Eddie and LeAnn [Rimes] deserve each other."