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<em>PREMIUM-EXCLUSIVE</em> Khloe Kardashian finally reveals her post-baby body!

Kardashian, who welcomedaughter True Thompson four months agowith boyfriend Tristan Thompson, hit the beaches ofPuerto Vallarta, Mexico, in a cheeky one-piece (her favorite swimsuit style!) which put her famous curves on display. The new mom is on vacation with her boyfriend, sisterKendall Jennerand the model’s basketball player beauBen Simmons.

“Khloé and Tristan seemed very happy,” a photographer source tells PEOPLE of the new parents on vacation. “Lots of cuddles and love all weekend. They definitely enjoyed themselves.”

RELATED VIDEO: Khloé Kardashian Shows Off Her Abs in Mexico 4 Months After Giving Birth to Daughter True

Kardashianreturned to the gym six weeks after giving birth, as soon as she got clearance from the doctor. But the star revealed ittook her time to get back into her routine.

“The first day, I could not do the most simple things. I was out of breath. It was just different. And I kind of felt really defeated. Like, ‘Oh man. I don’t know if I can do this,'” she said. “After the first week I was like, ‘Okay. I am feeling a little better.’ I am not breathing so hard. I don’t need as many breaks. But I would say really after three weeks was when I felt good.”

As for adjusting to mom life, the star says she has a new-found appreciation for what her sisters went through.

Earlier this month, she expanded herGood American brand with the launch of a new athleisure linefeaturing a size-inclusive range of workout clothing designed to make women feel confident and comfortable at the gym.

“Moving into activewear was a natural next step for Good American,” Kardashian tells PEOPLE exclusively of the exciting new launch. “When we think about new categories, our biggest priority is to always provide women with wardrobe staples, giving them options to get them through their busy daily lives and that make them look and feel their best. Fitness is my passion so I am so excited for this and can’t wait to share it with everyone.”

source: people.com