Sean 'Diddy' Combs Is 'Beside Himself' Over Ex Kim Porter's Death: 'He Isn't Sleeping,' Says Source

Less than a week after Sean “Diddy” Combs‘ former romantic partner — and mother of four of his childrenKim Porter was found dead in her home, the 49-year-old hip hop mogul is reeling from the sudden loss.

“This is the most awful, sad and unreal situation for him. It’s a nightmare,” a source close to Combs tells PEOPLE. “He is very much struggling. He isn’t sleeping. He always had a very special relationship with Kim. Despite not being together romantically, he loved Kim. It was really true love and he is hurting badly right now.”

RELATED: Diddy Shares Memorial for Kim Porter & Promises to ‘Raise Our Family Just Like You Taught Me’

Insiders tell PEOPLE that Diddy held a memorial for his former girlfriend at his Bel-Air home on Sunday afternoon. Among the 100 guests present were Pharrell Williams, Mary J. Blige, French Montana and Kourtney Kardashian.

Diddy and Kim Porter.
Diddy and Kim Porter.

“He is very involved in making arrangements for Kim. He wants it all to be very special,” the insider continues.

RELATED: Diddy Breaks Silence on Kim Porter’s Death: ‘I’ve Been Trying to Wake Up Out of This Nightmare’

Diddy showed a glimpse of the candle-lit memorial on his Instagram Story on Sunday.

“It was a beautiful memorial for Kim,” the source tells PEOPLE. “Diddy is still beside himself. He was very emotional, but grateful how many of his friends showed up to honor Kim.”

Diddy's memorial for Kim Porter.
Diddy's memorial for Kim Porter.

The Los Angeles County Sheriff’s Office confirmed Porter’s death in a statement. Officers were alerted after a woman was found unresponsive in Toluca Lake, California. She was declared dead at 11:40 a.m. local time on Thursday.

Her health status was described as a cardiac arrest in an emergency dispatch call obtained by TMZ. A source told TMZ that she had been battling pneumonia.

RELATED: Kim Porter Dead: Drake, Rihanna, Nicki Minaj & More Celebs Mourn the Model and Mother of Four

“Diddy is devastated and shocked,” a source previously told PEOPLE. “He and Kim were still very close friends and co-parents even though their romantic relationship didn’t work.”

“They were still a family,” the source continued.