Prosecutor Graham Reeds made the case against Robert Brown, 47, to a jury in Reading Crown Court Tuesday, the Daily Telegraph reported.
Brown is accused of smashing his wife Joanna's head with a mallet at their mansion in Ascot last Oct. 31, wrapping her body in plastic and burying it in a grave he had dug in advance.
The couple's two young children were in the home at the time.
The couple were married in 1999 after signing a prenuptial agreement to protect her wealth, The Sun reported, and the killing took place days before their divorce settlement was to be decreed.
Brown believed his wife had "cheated" and "manipulated" him, the prosecution said.
Brown admits attacking his wife with a hammer but says he was suffering severe stress from an illness that impaired his self-control. He denies murder and obstructing the investigation of his wife's death.