Teddi Mellencamp's expensive love affair led to divorce, devastating her family life and spending tens of thousands of dollars pursuing a married man.

Page Six reports that Teddi Mellencamp is accused of cheating on her estranged husband, Edwin Arroyave, with a married friend.

A source familiar with the situation revealed that Mellencamp, 43, is alleged to have spent the night with a longtime friend, whose wife was also a close friend at the time, on Arroyave Street, 47, several times, starting in May.

Page Six has identified the man as Simon Schroeder, Mellencamp’s horse trainer, and the woman as Karli Postel. Daily Mail was the first to report their identities. Schroeder and Postel, who have two children together, declined to comment when Page Six reached out.

Teddi Mellencamp allegedly cheated on her now-estranged husband, Edwin Arroyave, with a married friend, Page Six is told.

An insider tells us Mellencamp allegedly stepped out on Arroyave several times with a longtime pal, whose then-wife was also a close friend, beginning in May.

The source said Mellencamp and Schroeder traveled to Florida together to attend an equestrian event while Postel was in California giving birth to their second child.

Page Six can identify the man as Simon Schroeder, who is Mellencamp’s horse trainer, and the woman as Karli Postel.

Postel and Schroeder share two children.

“Karli was suspicious when her husband was in Florida while she was giving birth,” a source told Daily Mail. When Schroeder returned to Los Angeles, the source said Postel allegedly found inappropriate text messages between him and the former "Real Housewives of Beverly Hills" star, leading to a public confrontation.

“They confessed. Teddi promised it wouldn’t happen again,” the Daily Mail source said, adding that “Karli didn’t tell Edwin when she discovered it” because “she wanted to give Simon another chance.”

However, the Daily Mail source claimed that Postel learned last month that the alleged sexual affair between Schroeder and Mellencamp had not only continued but had become “emotional,” so she informed Arroyave.

Our insider tells us Schroeder and Mellencamp were in Florida together for an equestrian event while Postel was in California in labor with their second child.

“Karli thought it was suspicious that her husband was in Florida when she was giving birth,” a source told the Daily Mail.

The insider confirmed that the reason Mellencamp is divorcing is due to the affair between her and Schroeder.

“She filed for divorce from Edwin so he wouldn't have the chance to file and accuse her of adultery,” the source from Daily Mail said. “People believed the marriage ended because Edwin cheated on Teddi, but the truth is the opposite.”

Both Mellencamp and Arroyave declined to comment when contacted by Page Six. The former Bravolebrity filed for divorce on November 1 and listed their separation date as October 20—although she and Arroyave appeared affectionate at a charity event just four days later.

When Schroeder returned to LA, our insider tells us Postel allegedly discovered inappropriate text messages between him and the “RHOBH” alum, which led to a heated public confrontation.

“They confessed. Teddi promised it would not happen again,” the Daily Mail’s source said, adding that “Karli didn’t tell Edwin when she found out” because “she was willing to give Simon another chance.”

Mellencamp is seeking primary legal and physical custody of their three children—daughter Slate, 12, son Cruz, 10, and daughter Dove, 4—with Arroyave granted "reasonable and frequent" visitation.

In his response, the former CEO of Skyline Security listed the separation date as November 1 and requested joint legal and physical custody.

On November 2, Mellencamp announced she would divorce Arroyave after 13 years together. “After much consideration and careful thought, I have made the difficult decision to file for divorce,” she wrote in a statement posted to Instagram. “My priority is the children and ensuring that all care is carried out with their privacy and happiness throughout this new chapter.”

Mellencamp—the daughter of famous musician John Mellencamp—noted that "making a public statement" "was not something I wanted to do," but she felt being "open, honest, and vulnerable" would help "protect [her family] from unnecessary speculation and rumors."

For his part, Arroyave hinted at the split through his Instagram Story with a mysterious message about “dark days,” a selfie showing him and the children heading to church, and several Bible verses related to praying for the children.

Teddi Mellencamp not only got entangled in a much-criticized affair but also “splurged” tens of thousands of dollars on this relationship. To maintain the illicit connection with Simon Schroeder, Mellencamp spent a fortune, only to face the bitter end of a divorce with Edwin Arroyave, who now knows everything.