Kenny Chesney is blasting a tabloid report that he and Jessica Simpson flirted in front of Tony Romo at a July 4 party just days before the couple's breakup.

"Tony's a friend, and I wouldn't flirt with a buddy's girlfriend," Chesney tells PEOPLE. "More importantly, Jessica was just being sweet and there was nothing else to it. It's not funny. There were no problems. Everybody got along great. After the party, everybody went their own way and nobody thought anything more about it. Period. End of story."

The party was thrown by Chesney's friend, Sean Payton, coach of pro football's New Orleans Saints, Chesney says.

"If a girl and her boyfriend can't go to someone's house for a Fourth of July party and talk to the other guests without it turning into a big nightmare ... , then I feel really sorry for Jessica and Tony, who're both really nice people," Chesney says. "I wonder if I wasn't famous if anyone would even care. But the fact of the matter is I talked to a bunch of guests, hung out, had a good time."

Simpson and Romo, the quarterback for the Dallas Cowboys, split five days later on July 9 - the night before Simpson's 29th birthday.