She told Us Weekly magazine of her heartbreak, but insisted that the pair are still friends.
The Liz & Dick actress said: "I need to love myself first before I could be with anyone else, and I was going through a lot. Two toxic people cannot be together. End of story. We're friends now. That's how it started so I think that's how it was meant to be.
"I was bold enough to say, 'Yeah, I like a girl. And?' That put her in a situation where she was being attacked every day.
"That's not fair. And what am I left with? Heartbreak. That was three years ago. It was my last serious relationship."
When asked about her infamous partying, she put her lifestyle down to "bad influences".
The 26-year-old told the magazine: "Kids go through ups and downs, try cigarettes, drugs and drinking. It's human nature.
"It took a while but it's like, what was I thinking? Why did I allow so many sycophants and bad influences to be around me? I was lonely and I didn't realise it.
"That's why I came back home to New York. I never feel lonely there. I can see my family and I have really good people in my life."
Lohan stars in Liz & Dick as Elizabeth Taylor, but was described as being difficult to work with by producer Larry A Thompson.
Lifetime will air Liz & Dick on Sunday, November 25.
Watch trailer for Liz & Dick below: