The 27-year-old national team and Orlando Pirates goalkeeper and captain, who was married, was shot dead at about 20:00 in Vosloorus on Sunday.
Police spokesperson Brigadier Neville Malila could not confirm earlier on Monday whether Meyiwa was at Khumalo's home when he was shot.
This is what some Twitter users had to say:
I feel sorry for #SenzoMeyiwa's wife who had to deal with a cheating hubby & now his death, as for #KellyKhumalo can go swim with the sharks
— Bayanda Bikitsha (@Bayanda_B) October 27, 2014
Whoever is investigating #Senzomeyiwa's murder makaqale ngo #KellyKhumalo or his wife. I smell a foot of a baboon...
— Hands OffBuyelekhaya (@ghettostyler) October 27, 2014
@Kelly_Khumalo Yiu see what messing in someone's marriage does; you should be stoned you adulterous witch
— NganekaMama (@NganekaMama) October 27, 2014
However, many users also defended Khumalo.
Mlacash Wamampela tweeted: "Kelly Khumalo must be traumatised... why are people being so mean to her though, whatever happened to empathy?" and Thembelihle Cele said, "Shame on all of you talking smack about @Kelly_Khumalo. Regardless of what you think of her, she's human, and she's going through it!"
Khumalo is the mother of a child with Meyiwa, and she also shares a child with hip hop singer Molemo "Jub Jub" Maarohanye.
Maarohanye was found guilty of murder for killing four schoolboys while drag racing down a Soweto street while high on drugs. This was later converted to culpable homicide. His sentence was reduced to 10 years imprisonment, two of which were suspended.
A confrontation between Meyiwa's wife Mandisa, and Khumalo, reportedly ended with the singer's arrest last year after she allegedly assaulted the wife near the Empire road off-ramp.
Meyiwa reportedly told police his wife had provoked Khumalo.
"Kelly had no idea that I was in a relationship, I didn’t reveal it to her. I should have known and done better, I have apologised to both Mandisa and Kelly for this," Meyiwa said at the time.
Khumalo posted a picture of herself with Meyiwa to Instragram several hours before the shooting on Sunday.
No arrests had yet been made and police were investigating a case of murder.
National police commissioner Riah Phiyega would address the media about the investigation into Meyiwa's shooting later on Monday.