Kevin Federline admits that when he began seeing his now-wife, Britney Spears, the timing was less than ideal. "I'm not going to say that I planned on falling in love with my wife when my ex-girlfriend (actress Shar Jackson) was pregnant," Federline, 28, tells USA Today.

However, the rapper, whose debut album, Playing with Fire, hits stores Tuesday, says one thing wasn't a surprise: "I knew for sure that I'd have one or two children by now. I didn't think I'd have four children, but I love being a young dad with a big family."

His first child with Spears, Sean Preston, is 1, and their second son, Jayden James, was born Sept. 12. All four kids get along, Federline tells the newspaper. Sean Preston "gets real excited when Kori and Kaleb come over," and Jayden "picks up things a lot quicker than the others, because he has the benefit of learning from the older kids." His and Spears's older son, he says, "is starting to take on the big brother role, and he's getting very protective. (He) wants to be around the baby all the time."

Federline also says he thinks show business is no place for children, "even though my wife did it, and it turned out okay for her. … And if that means I take my family out of L.A. to grow up on a farm, then that's what I've got to do." Spears, he says, has been "recording three or four times a week, and she still manages to be with the kids a lot."

He and his wife take on different parenting roles, he says: "She spoils them; I'm the enforcer." Little Jayden James hasn't yet made his public debut, and Federline says Spears will decide when to release a photo. "But if my wife wants to have that baby all to herself for now, then she keeps it, because there's not much she has to herself," he says, "not even her own children."

Federline also tells his life story to the The New York Post, and says he wants to write a book: "The book is definite. It will be a biography of my life until I met my wife, so people will better understand who I am. I haven't done it yet. You know, I'll get a ghostwriter in there."

Another, perhaps surprising, goal for the future: "I want to go to Africa – I think it's a place where you can go and really, really help people and make a difference. And it's also a place I want to see – I'm into the safari animals and all that stuff. I grew up watching the Discovery Channel."