Sam detailed the abuse further in another post on Believe, describing her experiences with gaslighting and psychological manipulation.
"I thought I was madly in love and had finally found my soul mate," the Bachelorette star said.
The actress said her ex would make her "crazy and paranoid."
"My partner at the time made me feel like I was completely mentally unstable, he repeatably told me I needed 'serious help,'" she wrote.
"Somehow he manipulated the situation and said I was to blame for being crazy and paranoid, to the point where I stayed with him after the fact because by that point I was weak, fragile, depressed and felt worthless. He would say things to me like, 'Sam, why do you think every guy has broken up with you?' And I would reply with a variety of reasons. He'd then say, 'Well there's a pretty clear pattern, they all leave you'."
Sam said that when she started seeing her psychologist, it was initially to "save" their relationship, but the step was the wake-up call she needed to leave the relationship.
"In the end, she didn’t save my relationship, she saved me," the 30-year-old confessed.
Sam also thanked her current boyfriend, Dave Bashford (who she has been dating for two years) for supporting her through her mental health issues.
"It takes great strength to sit in the darkness alongside the person you love," she wrote.
"You are the true hero."