The talk show host discussed her early romantic experiences during an upcoming interview on CNN's Piers Morgan Tonight.
"You have one relationship in your life that's kind of crazy and out of control a little bit and that usually doesn't last very long but takes you into the deep water," O'Donnell explained.
"It opened me up. I realised I was capable of risk taking. You have an idealism when you're a kid about what romance and family and forever means. I think at 28, 29 years old, you're ready to step into a mature kind of love, so that's what got me there."
O'Donnell spoke about her two-year relationship with a man named Mike, who she lived with at the time.
"There was something really glorious about being in a relationship at the supermarket with your partner, getting stuff for the football game on Sunday and having the cashier say, 'How long have you guys been dating?' When you're there with a woman, with your same sex partner, no-one asks," she said.
O'Donnell recently described Rounds as "literally perfection", saying that she felt lucky to have snagged such a beautiful woman.
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