When she achieved success by her mid-20s, she wasn't able to handle it well.
"It was tough," Summer said. "I think success is always a surprise, you know."
She eventually suffered depression and found herself in an abusive relationship.
"If people are in abusive relationships, I think they need to get out of them or at least get help," Summer said.
She lived in fear during that relationship, she said.
"Thank God this person was from Europe, so they were deported. And then I was able to sort of be free, but I was afraid for years," she said.
Her hits included "Hot Stuff," "Bad Girls" and "She Works Hard for the Money."
Summer rose to fame the mid-1970s, thanks to "Love to Love You Baby." The song, with Summer's whispered vocals and orgasmic groans supported by heavily synthesized backing tracks, fueled the decade's disco mania and hit No. 2 in 1976.
Summer followed the song with such hits as "I Feel Love," "Last Dance" and a disco version of the Richard Harris hit "MacArthur Park," which outdid Harris' version by hitting No. 1 on Billboard's Hot 100 singles chart. It was Summer's first of four chart-toppers.
But with her 1979 album "Bad Girls," Summer broke out of the disco mold as the genre, stimulated by the success of the Bee Gees' "Saturday Night Fever" soundtrack, was feeling a backlash. "Bad Girls" demonstrated Summer's vocal and stylistic range and produced two No. 1 hits, "Hot Stuff" and "Bad Girls," as well as a Top 10 ballad, "Dim All the Lights."
However, Summer had some trouble adjusting to the changing times. Her next album, "The Wanderer," went for more of a rock feel. It produced a Top 10 hit in the title track but fared relatively poorly on the charts -- especially disappointing after the success of "Bad Girls," a double album that spent five weeks at No. 1.
It wasn't until 1983's "She Works Hard for the Money," which became a ubiquitous video as well as a big radio hit, that Summer's fame approached its late-'70s zenith.
CNN's Denise Quan and Todd Leopold contributed to this report.
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