Seedat searched online for terms such as "cremating a body", "best place to knock someone out" and details on how to bury someone alive.
He then struck his wife of eight years with a wheel brace as she slept.
She woke up after the first blow but was easily overpowered by him as he continued to attack her, while the couple's two children slept soundly in a separate room.
He then choked and suffocated her, before burying her in a hole he'd had dug in their backyard. He told the contractor digging the hole that it was so he could install a pool for his two children, aged 2 and 5.
Seedat said her final words to him, as he attacked her, were "I love you".
After her death, he lied to friends and family, telling them she'd gone to the UK for eye surgery. He told his sister-in-law she had left him.
"It may have been technically clumsy but it was calculated behaviour," the judge said.
"You envisaged a future with your sister-in-law … you had become emotionally dependent on her."
Seedat had also searched online "Can you marry your brother-in-law if your sister is dead muslim?"
Seedat is also facing separate fraud charges, with allegations he stole A$5.7 million.