“For the last three days I’ve been trying to wake up out of this nightmare. But I haven’t,” he wrote on Saturday, alongside a throwback video of the pair posing together for a pregnancy photoshoot.
“I don’t know what I’m going to do without you baby. I miss you so much,” he continued in the emotional Instagram tribute. “Today I’m going to pay tribute to you, I’m going to try and find the words to explain our unexplainable relationship.”
Continuing, he wrote that “We were more than best friends, we were more than soulmates. WE WERE SOME OTHER S—!! And I miss you so much. Super Black Love 🖤.”
A source previously told PEOPLE that the music mogul, 49, felt “devastated and shocked” by Porter’s death.
“He and Kim were still very close friends and co-parents even though their romantic relationship didn’t work,” the source said. “They were still a family.”
On Thursday, Porter, who was a model and actress, was found dead in her home. She was 47.
The Los Angeles County Sheriff’s Office confirmed Porter’s death in a statement explaining that officers responded to a death investigation at 11:40 a.m. local time in Toluca Lake, California, where they found a female unresponsive at the residence.
Porter was pronounced dead at the scene.
Her cause of death remains undetermined at this time. According to an emergency dispatch call posted by TMZ, the call came in as a cardiac arrest. A source told the outlet she had been suffering from pneumonia for weeks.
Combs and Porter began dating in the ’90s and split for good in 2007 after years of an on-and-off-again relationship. Together, the pair had three children: son Christian, 20, and 11-year-old twin daughters D’Lila Star and Jessie James. Additionally, Combs raised Porter’s eldest child, Quincy, 27, and considers him a son.
The Bad Boy Records entrepreneur is also the father of two additional children — son Justin, 24, and daughter Chance, 12 — whom he shares with exes Misa Hylton-Brim and Sarah Chapman, respectively.
Despite having split over a decade ago, Combs and Porter were able to remain friends over the years as they continued to co-parent their children.
“I’ve been truly blessed to have some great, incredible relationships that have afforded me these children by these very strong, intelligent, beautiful black women,” Combs previously told PEOPLE of his exes. “The mothers of my children [are] my best friends. My hat goes off to them.
“We’re friends. I’m the person he can tell his innermost thoughts to and he’s that person for me. He still calls me every day and we talk,” Porter also told Essence.