Jason Derulo Says Co-Parenting 6-Month-Old Son with Ex Jena Frumes Is 'Amazing'

Jason Derulo might be ridin' solo, but he still has a lot of love for his ex-girlfriend Jena Frumes.

The "Savage Love" singer — who redefines the "dad bod" in PEOPLE's 2021 Sexiest Man Alive issue, on newsstands now — says that despite their breakup in September, he and the model are on great terms and focused on co-parenting their 6-month-old son, Jason King.

"It's a beautiful thing [that we can support each other], especially given our new relationship: co-parenting," Derulo tells PEOPLE. "We have an amazing relationship, and we don't care if we're confusing people about our situation because our situation is our situation."

"We love [our son] more than anything, and his wellbeing is really important to us," he adds. "I'm really attentive of her wellbeing as well, and I want her to be good. I care about her a lot. We have an amazing relationship, contrary to a lot of people's beliefs."

As to who baby Jason King takes after looks-wise, Derulo, 32, says "he's a little more light-skinned than I would've expected."

"I thought he was going to come out as a spitting image of me!" he says with a laugh. "I don't know why I thought that, but for some reason I did. But he has my lip shape."

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Personality-wise, though, Derulo says the apple doesn't fall far from the tree.

"He's a little feisty, so I think he gets that from both Jena and I," he says. "We were born on the same day, Jena and I, so I think we both have a bit of fire in us. When he's ready to wake up, he's going to let you know that it's time to get up."

Throughout the day, Derulo says that he and his son can typically be found watching TV together.

"I love to watch the things that I love to watch with him," he says. "I think he's still young enough where he doesn't really understand what he's watching, but I love watching cartoons with him too. I think he brings out the child in me again."

"It's amazing to share all the first times with him," he continues. "The first time he had a strawberry and the first time that he actually paid attention to what was on the television ... I can't wait until he says 'dada' because I think that's probably going to be his first word."

No matter what they're doing, Derulo says his dog Ice can always be found close by.

"It's his best friend in the world," Derulo says. "This is Ice's baby. He's like, 'Don't you hear it? My baby's crying. What are you doing?' He does not want to leave his side."

Since welcoming Jason King in May, Derulo says his whole outlook on life has changed.

"I think when you're chasing your goals, your goals are usually very selfish," he says. "But having him has completely shifted my mindset. Now it's about, 'How do I become the best inspiration for him? How do I make sure that I'm in a position where I can help make his dreams come true?' That shift is probably the best thing that's happened to me. It's a whole new reason for thriving."

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As Jason King gets older, Derulo hopes that he continues to take after him, particularly when it comes to the gym.

"He's definitely going to be a young gym rat," he says. "I think the earlier that you can start the better. I won't start him with weights right away, but I'll be getting him into sports, learning how to work out with pushups and pull-ups and learning the basics."

"I think it's important to teach your kids young so that it becomes a part of their lifestyle and not something that they dread doing," he continues. "I wake up in the morning, and I know I have to eat at some point. It should be the same way with working out. You wake up and you know in that day you have to work out. It should go hand-in-hand."

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Derulo often works out two times a day now, focusing on one body part in the afternoon and cardio in the evening.

"I find, for me, if I'm not working out twice a day, I look really regular," he says. "It's only when I add that second workout that I feel like it just pushes me up a notch. Sometimes life gets in the way, but I always work out at least five, six times a week. Right now it's probably 12 times a week. I like being a beast in the gym."

In addition to his consistent workouts, Derulo says he also watches what he eats.

"I can't eat what I want," he says. "Some people have a voice in their head that says, 'You've had enough.' I don't have that voice.' I just keep going and going and going. I really have to be careful with my intake because I eat a lot."

Derulo admits though that that there are certain foods he can't say no to — cookies, lava cake and Olive Garden's seafood portofino included. To celebrate his massive following of more than 50 million on TikTok, he's also thinking of hosting a "crazy cereal party."

"I was thinking about filling my pool with cereal and inviting a bunch of people over to have a crazy cereal party — a 75-foot pool just full of cereal and milk," he says.

While he's been enjoying all of the viral success, Derulo says there's nothing he's more grateful for than his family.

"I keep my family very close to me," he says. "I wouldn't be here today without them."