Christine Solik, 57, who is originally from Mountain Ash, was found bound and murdered 50 miles (80km) from her home in the Kwazulu-Natal province on 17 February.
The body of her husband Roger, 66, who suffered from Parkinson's disease, was found over a mile from her on Monday.
Police in South Africa believe the couple had been kidnapped from their home during a robbery on Friday.
The couple married in Wales in 1980 and travelled to South Africa the following year.
Their four children, Alexander and Gregory, 32, Jessica, 30, and Brendon, 29, issued a statement saying: "Our parents were inseparable and their relationship was something to aspire to.
"It is hard to understand that on their community farmland estate, with rolling hills and endless nature, and neighbours 100m away, that something so violent could happen. Please keep us in your thoughts and prayers."
Mrs Solik had returned to Wales for the funeral of her father, Glyn Savage, last month.
The couple, who also had two grandchildren, Xavier and Lucy, initially emigrated on a two-year visa, but decided to stay in South Africa.
A couple from south Wales have been found murdered in South Africa.