updated 03/14/2011 AT 2:00 PM ET
•originally published 03/14/2011 AT 2:40 PM ET
Two days after the former couple drove together to a Hollywood In-N-Out Burger, Wentz, 31, called into Ryan Seacrest’s KIIS-FM morning show to discuss his new band, Black Cards, and to praise Simpson, 26.
“It’s like Ashlee’s been my best friend for five years,” Wentz said Monday. “She’s the mother of my child. I have nothing but love and respect for her. Going through something like this isn’t easy, but we’re friends, and the most important thing is to put our son first.”
Wentz says keeping the details of his divorce private is tough, though, fortunately, the celebrity news cycle has been busy lately.
“It’s hard to maintain your private life,” he says. “You want to do it, especially when there’s a kid involved. It’s like the one time on earth I’m like, ‘Thank god Charlie Sheen exists.’ ”
In spite of it all, the rocker says his son’s spirits are high.
“He’s doing awesome,” Wentz says. “He’s crazy. It’s like something new everyday. Everything’s like a new discovery for him. All of a sudden he’s opening doors and all of a sudden he wants to paint.”
“His new thing is hiding cell phones and credit cards and stuff,” Wentz continues. “I’m like, ‘So where’s dad’s cell phone?’ And he laughs. He thinks it’s a comedy bit.”