"Tony is a great quarterback, but he's a better boyfriend," Simpson, 28, told PEOPLE at a Nina's Night Out, a benefit for the Rape Crisis Center at the Palms Casino Resort's Pearl Theatre in Las Vegas on Thursday. "I'm seriously proud of myself for letting him into my life."
Romo "was my Monday this week," joked Simpson, in reference to her song about him, "You're My Sunday," and the Dallas Cowboys' huge win over the Philadelphia Eagles on ESPN's Monday Night Football a few days ago.
The NFL star is also someone else's hero: He recently stopped to help a couple change their flat tire in Texas Sept. 7.
"Through all the chaos and torment and everything I go through, I can lay in his arms and finally rest," she added.
Having her cuddled up next to him isn't always such a relief, admitted Simpson.
"To be my man, you have to put up with a lot," said the singer. "I toot under the sheets, I spend a lot of money and I can belch the ABC's."
On Forgetting LyricsDuring her 70-minute set featuring her album, Do You Know, which debuted at No. 1 on Billboard's country music chart this week, Simpson forgot the lyrics to one of her best-known pop songs, "With You."
"I did the same thing on Good Morning America," said an apologetic Simpson, referring to her tech-challenged TV spot before starting the song over again.
Afterwards, she said, "I've been singing that song for about 70 years and I forgot the lyrics. At least you guys knew them."
Simpson continues her hectic promotional schedule, when she performs this weekend at the Los Angeles County Fair in Pomona, Calif.
"I've been to 12 states in the past week," she said. "I'm exhausted, but it's worth it. I can't believe I have the No. 1 album in country right now."
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