"I'm definitely still working out, but I do less intense workouts because I'm not getting as much sleep now," Lopez tells PEOPLE during an appearance at Manor Nightclub in Chicago. "So the fitness [regimen] is still intact, but lately I just haven't been able to go at it as hard as I used to."
But the doting dad, whose daughter Gia was born Sept. 11, just couldn't be happier to be a father – with or without his signature six-pack abs. "I love [being a dad] more than anything," he says. "I absolutely can't wait to get home to see her – she's so amazing. The whole experience is so amazing."
Being a new parent isn't without its fair share of surprises, though.
"The biggest surprise about becoming a father was watching her being born because I didn't know if she was going to be girl or a boy," Lopez, 37, says.
Even though he didn't know the sex until the baby was born, he had a hunch it was a girl. "The way [girlfriend Courtney Mazza] was carrying and everything else, I had a feeling it was going to be a girl – and I was right."
As for diaper duty, Lopez says he's all over it. "Oh yeah, I'm definitely hands-on, changing the diapers and everything," he says.
And when it comes to keeping the romance alive with girlfriend Courtney Mazza, he's got that in the bag as well.
"I think it's definitely important to still do date night and keep the romance there," he says. "We are making an effort in that department."
Lopez will be letting the world see just how chaotic his life really is when his new reality show debuts on VH1 on Nov. 1. "Oh yeah, you'll see it all," says Lopez. "We did everything at once: new baby, new house, new puppy – lots of changes going on."