The two reconciled and had their last born child in January last year.
"I treated them like they were all my children. I am shocked. I can't believe she did this," he said.
Shongwe said he was not ready to face Maditla and talk to her about what happened.
"I don't know what I would say to her. I am not ready. I was angry at first and I wanted to ask her if she really did this," he said.
Maditla is expected to apply for bail in the Witbank magistrate's court next week.
Maditla's family said they were not aware that she had been financially struggling to raise the children because she did not open up about her problems. A relative, Kate le Grange, said Maditla was an introvert.
"She is not a person who opens up to us as her family.
"We are shocked [but] justice must take its course because lives were taken in a brutal manner," she said.