The former fiancés split in February

Rob Kardashian is declaring his love for Blac Chyna.

In a heartfelt Instagram post on Tuesday, thereality star shared a throwback photo of his former fiancé, and penned a heartfelt caption about the mother of his first child.

“On my first episode of Rob’s Random Cornball Thoughts is This young lady who grew up to be the woman I love and the mother of my child,” Kardashian, 30, wrote about Chyna, who is sitting on a bed in the old photo.

“She is beautiful and gave me my first child. @blacchyna,” he concluded.

Shortly after, Kardashian posted a second photo of Chyna at the age of 14 sporting SpongeBob Squarepants boxers.

“Awww look at my little Angela at 14!!!!!! Hahaha I LOVE YOU !!!! @blacchyna,” he wrote.

The ex-fiancés, who first split in March 2016, experienced their fair share of ups and downs throughout their yearlong romance, right from the outset of their relationship last January.

Kardashian proposed to Chyna, 29, in April 2016, and a month later, they announced they were expecting their first child. The two welcomed their daughter, Dream Renée, in November.

After a year of ups and downs, including screaming matches, therapy sessions and even a paternity test, which were documented on their E! reality show Rob & Chyna, and a fight that nearly ended their engagement right before Christmas, their romance came to an end in February.

“They split a while ago. The wedding plans are off,” a source close to Kardashian told PEOPLE. “They are both trying to be mature about it. It was less dramatic this time.”

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Although the couple attempted to make their relationship work, an insider told PEOPLE that Chyna became frustrated with Kardashian over time.

“Chyna is super fed up with Rob and thinks he is way too emotional and depressed. She thinks he has terrible issues,” said the insider, who knows both Chyna and Kardashian. “He is always battling his own insecurities and is unstable. It’s a major turn-off to her, and she thinks it’s incredibly unhealthy for the baby and their family.”