Jana Kramer Files for Divorce from Mike Caussin: 'He Cheated and Broke Her Trust,' Says Source

Jana Kramer has filed for divorce from Mike Caussin.

On Wednesday, the country singer and actress, 37, announced in an emotional social media post that she is splitting from Caussin, 34, after six years of marriage.

"'It's time.' As I try to make sense of a reality I never wanted to believe could be possible again, those words have now become a reality," she wrote on Instagram. "I've fought y'all. I've loved hard. I've forgiven. I've put the work in. I've given everything I have, and now I have nothing else to give."

"Please know that I still believe wholeheartedly in marriage, love, and rebuilding. I just can't fight any longer. It's time to heal," she continued. "Thank you for all the love, heart, and support, in many ways you have fought on this journey alongside me, and for that I am grateful. I'll always encourage you to continue the good fight, but you can't fight it alone. 💔"

RELATED GALLERY: A Complete History of Jana Kramer and Mike Caussin's Rollercoaster Relationship Leading Up to Divorce

A source tells PEOPLE that the divorce is due to infidelity, which the couple had previously separated over in 2016.

"He cheated and broke her trust again," the source says. "After fighting for the marriage for so long, she's come to terms with the realization that his patterns were never going to change."

"The focus now is on their kids," they add, referring to the couple's children Jolie Rae, 5, and Jace Joseph, 2.

A rep for Caussin did not immediately return PEOPLE's request for comment.

Listen below to the episode of our daily podcast PEOPLE Every Day for more on Jana Kramer and Mike Caussin's split.

The news of the split comes seven months after the couple released their book The Good Fight: Wanting to Leave, Choosing to Stay, and the Powerful Practice for Loving Faithfully about strengthening their marriage after the former football player sought treatment for sex addiction.

"I've dated only a few women in my life," the former NFL player wrote in it. "Most of my relationships can be more described as 'talking to,' which essentially means we were sleeping together but I never committed enough to get my feelings involved. And when I did commit, I inevitably cheated. I couldn't be alone."

"Now, I loved and still love being Jana's husband, but early in the relationship I had no idea who I was anymore," he later added.

Kramer has been open about Caussin's multiple affairs in the past, specifically those in 2016, the same year the two separated. (They renewed their wedding vows in December 2017.)

"The pain consumed my every thought and physically hurt me more than I thought I could handle," she wrote in an essay for Good Morning America. "Thinking back, it seems like a terrible nightmare that I wouldn't wish on anyone."

And while Caussin's decisions were difficult to swallow, she wrote then that she "grew in therapy" and "grew as a partner" because of the work he was "doing on himself."

Around that time in 2016 — when she was on Dancing with the Stars and he was getting treatment for sex addiction — the couple revealed that Caussin actually filed for divorce and that the two separated for several weeks. (They read passages from their book on their Whine Down podcast.)

"Mike was in rehab and I was in an all-out war with my emotions. Most days, I would push Mike out of my brain and tried to live in the world as if he didn't exist," she read from The Good Fight. "Other days I was too weak to push and I missed him, and I hoped he would be in the audience watching me perform, rooting for me."

"There are so many days during the first year of our reconciliation, after the discovery of my affairs, when we thought, 'What the f--- is going on?' Honestly, most days were like that," he read from another passage of the book. "Needless to say, many of those days were filled with pain and hurt and sadness and despair."

In late March, Kramer shared a selfie of herself crying following a blow up fight between her and her husband.

"Nothing is perfect," Kramer wrote then. "I took this picture to almost remind myself that even though in the moment it seems like everything is doomed it's not."

"No relationship is perfect and when blow ups or fights happen sometimes we believe it's done and over but really it's a moment for growth and more understanding and to lean into your partner," she added.

"Just know it's not the end of the world," she continued. "And we all have these moments so ur not alone. Fights happen. No relationship is perfect.. Now the Important thing is in the end are you fighting the good fight together? ... ur not alone in ur struggles xo."