Michael Philpott is accused of hatching the scheme to set up his former mistress and diminish her chances of winning an upcoming residency court hearing involving their children.
Jurors at Nottingham Crown Court, where he and his wife Mairead are on trial for the manslaughter of the children, heard that Philpott was angry when Lisa Willis ended their 10-year relationship three months before the blaze.
He embarked upon a plan to set her up and point the finger of blame at her for setting fire to the home in Victory Road in Allenton, Derby, it is claimed.
Mick and Mairead Philpott's children – Jade, 10, and her brothers John, nine, Jack, eight, Jesse, six, Jayden, five, and Duwayne, 13 – all died after the fire which engulfed their home in the early hours of May 11 last year.
Richard Latham, QC, told the jury: "Michael Philpott was the prime mover and dominant player in this unlawful and highly dangerous enterprise that, in the end, went horribly wrong."
Part of his motivation may also have been to get a bigger home for the family, which may have persuaded Ms Willis to come back, the court heard.
Mr Philpott denies six counts of manslaughter in relation to the deaths. His 31-year-old wife and a third defendant, 46-year-old Paul Mosley, also deny the same six charges.
The trial continues.