Jim Smeal / BEImages / . 1 / 7
Jim Smeal / BEImages / . 1 / 7

In August, Jana Kramer announced that she and her husband of 16 months, ­Michael Caussin, were separating. At the time, he was in rehab, but it was unclear why.

According to Us Weekly, he was in rehab for sex addiction, because, he's a "sex addict" who cheated on the country cutie many times, including with a paid escort.

"Mike cheated on her multiple times with multiple women," a source told the mag for it's cover story, a damning report that bares the headline "Married to a Sex Addict."

The story goes on to claim that Jana always had her doubts about the former NFLer, who she met in the summer of 2014. He allegedly cheated on her two months after they started dating. The two even briefly split, but he charmed his way back to her.

Still, even as the "Dancing With the Stars" contestant was finalizing details of their May 2015 wedding, she was apparently suspicious, the mag claims.

When he was away on his bachelor weekend, she borrowed a friend's phone to try to catch him cheating. "She texted him, saying something along the lines of 'Had fun last night,'" the source says. "She was trying to bait him to see if he had met anyone."

The former "One Tree Hill" star knew of his wandering eye but thought he was a changed man.

"She told friends she really believed the cheating would never happen again," a pal said, who later added, "things were not any better" once they got hitched and had a baby.

Jana started hearing rumors of his cheating ways again.

"Nashville is a small town," the source said, "so people would tell her things about his cheating."

Quite literally taking matters into her own hands, Jana looked through her man's ­cellphone.

"She saw some texts," reveals the source, but added that it still took time for her to leave Mike because, as the source bluntly puts it, "she loves being in love and tends to turn a blind eye to trouble."

However, once she heard rumors that he was cheating on her with a paid escort, she had had enough.

"The only reason Mike got caught is because the escort knew Jana's friend," the insider said.

Mike later checked into a Hattiesburg, Mississippi, rehab, the same one where Tiger Woods sought treatment for his well-documented sex addiction. The source says Mike still wants to be with Jana, but remains unconvinced that it will happen.

"This is it," Jana's pal said. Another friend said, "She's focused on dancing, her baby and her new album."