lauren akins

Rhett's three daughters have since come around to the idea of a baby sister -- but maybe they'll still get a baby brother one day.

Thomas Rhett shared the news onstage in Texas ... and he also shared the sex of the new baby.

Rhett and Lauren have decided to be forthright about their ups and downs in the hopes that others won't feel alone.

Check out some behind-the-scenes photos before the show airs on Nov. 30.

These two are going to be very busy!

It's beginning to look a lot like Christmas ...

Happy Anniversary to these two lovebirds!

It's an almost unbelievable rustic retreat.

There was one particular moment when they knew things had to change.

In fact, the couple remains in close contact with their counselor to this day.