07/21/2008 at 11:05 AM EDT
broke down in tears as she performed at a country music festival in Wisconsin on Saturday night.
Playing to a crowd of several thousand – including boyfriend Tony Romo – at Country Thunder USA, Simpson told fans, "This is my first time being onstage in three years. Coming out tonight makes me extremely emotional, I'm so thankful for all of the personal struggles and all of the tabloids and all of the people that talk s---," she continued, choking back tears. "I'm so happy I went through that because it makes life so much more beautiful."
Simpson even dedicated a song to Romo, "You're My Sunday." "Tonight there's this guy here, he throws a football and he's really good at it, he's my better tomorrow and I wrote this song for him," she told the crowd.
She also addressed the difficulties surrounding her fame. "Any man that is going to date me has to put up with a lot," she said.
The crowd reaction to Simpson was varied: She received both applause and boos as she sang, and concertgoers gave mixed reviews to the Kenosha News
. "Just because she's dating [Dallas Cowboy quarterback] Tony Romo, it doesn't make her country," said Mike Rodriguez, 31, from Lake Geneva.
Other audience members were more positive. "I actually like her country songs better," said Mary Grace, 24. "She has a great voice, plus, she's adorable."
Talking into the mic, Simpson said, "I don't know what your perception is of Jessica Simpson or what tabloid you buy, but I just want you to know that I'm just a girl from Texas; I'm just like you. I'm doing what I love and dating a boy."
The Texas native, 28, is trying to cross over into a country career with her new single "Come On Over." The song is at No. 23 on this week's Billboard
country singles chart. Her country album, Do You Know?
, is due Sept. 9.
"She did really well," says event producer Gil Cunningham. "For her first country performance, she performed in front of more than 25,000 country fans. That's a big step to take."
As for the booing, "There wasn't much at all," Cunningham says. "I may have heard some when she mentioned Tony Romo. You're going to get booed when you mention him to a bunch of Packer fans."
Simpson opened her set with a cover of Nancy Sinatra's "These Boots Are Made for Walking" and sang covers of Willie Nelson's "On the Road Again" and Shania Twain's "Whose Bed Have Your Boots Been Under?"
Simpson's rep, Cindi Berger, tells PEOPLE that the singer felt "fantastic" about the show. "She loves getting out there and performing and being with her fans. She felt at home with country fans and the other country artists who were there."
After Romo and friends hung out on Simpson's bus after the concert, he and Simpson climbed into an SUV and headed out together.
Reporting by K.C. BAKER