Juan Pablo Galavis and Nikki Ferrell celebrated Juan Pablo's birthday at Flamingo Theater Bar on August 7, 2014 in Miami, Fla. So what went wrong? Us Weekly delves into why Nikki Ferrell broke up with her boyfriend Juan Pablo Galavis, the most controversial Bachelor ever -- get the details here. Credit: Gustavo Caballero/Getty Images

What went wrong? Us Weekly exclusively reported Monday, Oct. 27, that Juan Pablo Galavis and his girlfriend Nikki Ferrell had split, but who perpetuated the breakup and for what reason?

Sources tell Us that there has been trouble in paradise for the season 18 Bachelor and his winner for some time, but their rift intensified after the reality TV pair recently appeared on VH1's Couples Therapy.

"Juan and Nikki have been fighting," one insider says. The one to initiate the breakup was 27-year-old Ferrell, the source adds, noting: "It was not mutual."

Another insider familiar with the situation tells Us that the two wanted different things — a classic relationship killer. "Everything Nikki wanted, he didn't," the source notes. "She wanted to settle down and he didn't."

The same source adds that the former soccer player "stopped putting any effort in the relationship" after he and the pediatric nurse sought Dr. Jenn Berman's help on Couples Therapy.

"I don't think he ever said 'I love you' to her," the insider tells Us, which was a big struggle between the pair on the VH1 counseling reality show. As seen on one episode, Ferrell broke down into tears and questioned why she was in a relationship "if they're not giving you 100 percent?"

Galavis claimed in response that Ferrell had a "word issue" because "she wants to hear, 'I love you.'" He added, "If I say it, I mean it."

As fans know, Ferrell was the last-remaining lady on Galavis' controversial season of The Bachelor. During the After the Final Rose special in March, 33-year-old Galavis infamously refused to profess his love to Ferrell, warranting backlash from, well, America. See more of Juan Pablo's most controversial moments.

Still, a source close to Galavis tells Us that it simply wasn't meant to be. "They were not seeing eye to eye on anything," the insider claims. "Juan wanted Nikki in Miami. Nikki didn't want to leave her family, friends, or job. Meanwhile, Juan wouldn't even consider going to Kansas."

Indeed, the couple's final public appearance together was in August for Galavis' 33rd birthday party at the Flamingo Theater Bar in Miami (photo above). On Sunday, Ferrell hinted at her split on Instagram, sharing a rather telling quote that read: "Isn't it pathetic how we waste so much time on certain people and in the end they prove that they weren't even worth a second of it."

"Nikki felt like she was doing all the work in the relationship, and that Juan expected her to join his life," the last source tells Us. "She couldn’t get him to compromise at all."

Adds the insider, "He didn't put Nikki's priorities first and she had enough."