In an act of revenge, a woman in the US has mounted giant billboards of herself and her lover of eight years after discovering he was married.

The New York Post reports YaVaughnie Wilkins erected the massive photos in New York's Times Square, Atlanta and San Francisco with the words "You are my soulmate forever: Charles and YaVaughnie" splashed across them.

Wilkins' target was her partner Charles E. Phillips, a co-president of software maker Oracle and a member of President Barack Obama's Economic Recovery Advisory Board.

Oracle is one of the world's largest enterprise software companies.

Wilkins, 41, says 50-year-old Phillips told her he was separated from his wife, Karen, when the pair started dating in 2001.

Two years later he told her he was divorced.

"They lived together for the majority of their relationship," Wilkins's cousin Misha Davila told the New York Post.

"She thought she was in a long-term, monogamous relationship."

"It never occurred to any of us that he was still married."

The couple had moved into a $US11 million mansion together and reportedly attended sporting events with Phillips' son.

Two years prior, Phillips' had bought a house nearby with his wife, Karen.

According to the New York Post, Wilkins uncovered the extent of Phillips' deceit after receiving information from an anonymous source.

The billboards were erected soon after and may have cost Wilkins upwards of $55,000 each.