Jaimee Grubbs 'Felt Guilty' Sleeping With Tiger

Jaimee Grubbs admits she sometimes had second thoughts about sleeping with Tiger Woods, a married father of two.

"I guess if I were to think about it, I did feel guilty that he was spending his time with somebody that isn't his wife," she tells "Extra." "But you know, he never mentioned her. I never thought about it."

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By the time she learned he was wed to Elin Nordegren, "we already had this relationship," she says. "And he was the one who pursued me, and I just kind of got involved in this... I had invested emotions in it. I let myself think, 'out of mind, out of sight' type feelings."

Watch Jaimee Grubbs' apology to Elin Nordegren

Woods has been linked to 11 women, including Grubbs -- but she doesn't think he's a sex addict.

"The Tiger that I knew, I would never think that," says Grubbs, who has claimed she was intimate with Woods about 20 times over a three-year period.

Check out photos of the 11 women linked to Tiger

She admits that Woods has a "sleeping problem." According to reports, Nordegren told police that her husband had taken painkiller Vicodin and sleep aid Ambien before his Nov. 27 car crash.

"He did never sleep. I mean, even if he wanted to go to bed at maybe 10, he wouldn't fall asleep until 12:30, 1 [AM], and then he'd be up at 3," she continues.

Find out why Jaimee Grubbs released her text messages and voicemails with Woods

She credits his restlessness to the pressures of his athletic status.

"I'm sure he has so much on his mind, and I couldn't ever imagine it being put to sleep," she says. "He very much does have a sleeping problem."

For more on "Extra's" interview with Jamie Grubbs, tune in tonight!