Paris Hilton and Benji Madden
10/24/2008 AT 04:40 PM EDT
Benji Madden and Paris Hilton
's relationship is intact and better than ever, the Good Charlotte guitarist tells PEOPLE.
Reports that he cheated on his girlfriend of nine months
are "definitely not true," Madden, 29, tells PEOPLE. "It's very frustrating when you finally find yourself in a good relationship and people attack it. I wear my feelings on my sleeve. I'm very open about how in love I am – Paris and I are very happy."
Madden, whose band will release its next album, The Greatest Remixes
, on Nov. 25, says one of his and Hilton's relationship rules was inspired by Johnny Cash and his longtime love, wife June Carter Cash.
"I read this Johnny Cash book and it said they were never were apart for more than four or five days," says Madden. "So when Paris and I started getting serious, I was like, 'We shouldn’t be apart that much.' We try not to go longer than a week without at least seeing each other for a day or two. That's kind of our rule."
Next up for Madden: a new studio album due in 2009, and a tattoo parlor he and twin brother Joel Madden
plan to open with artist Mario Barth in Beverly Hills.
"Picture me and Joel having dinner at the Beverly Hills Hotel – we kind of get a little kick out of the fact that we get to go to places like that. That we could start a band in our garage and make this life for ourselves and then get to rub elbows with the society like that – Beverly Hills needs a tattoo shop."
So will Hilton get inked at Madden's new business? "I hope not," he says. "I like her the way she is. She's perfect. She's the most beautiful woman in the world. She doesn't need to change one thing."
Paris dishes on life behind bars on the cover of PEOPLE!