A source close to the couple exclusively confirmed the news to ET on Wednesday, revealing that Caussin is currently being treated in a rehabilitation center for undisclosed reasons.
Kramer, who is currently on tour and promoting her latest album, Thirty One, has been "trying to put on a brave face and do what's best for her daughter," a close friend of Kramer's says, adding, "she's been devastated by this."
And a brave face she's been putting on, indeed! Earlier today, Kramer took to Snapchat to share her excitement over her recent trip to Los Angeles, where she was traveling for her scheduled guest appearance on Chelsea Handler's Netflix show.
"I'm so excited, yay!" Kramer said in one of the videos. "Getting ready for the Chelsea Handler show, it's going to be so much fun."
While it appears Kramer has still been wearing her wedding band, she hasn't posted any photos of Caussin on social media in over a month. Their last photo together was this snap, taken seven weeks ago:
Kramer, 32, and Caussin, 29, started dating in August 2014, and the former NFL tight end proposed four months later. On May 22, 2015, the two said "I do." They welcomed daughter Jolie Rae in January.
ET caught up with Kramer at the Academy of Country Music Awards in April, her first red carpet appearance since giving birth to baby Jolie, where she gushed over Caussin's parenting skills and getting her body back in shape.
"Husband is amazing on diaper duty -- he's an absolute sweetheart, he's extremely hands-on, and I feel confident leaving and him knowing exactly what to do," she shared. "Most guys are like, 'I don't know what to do,' but he's super hands-on and absolutely amazing."
"But I've been working out a bunch and just trying to be confident and be like, 'You know what, I'm a mom and I'm embracing the new me!'" she added. Hear more in the video below.