Kourtney Kardashian used sister Kim and Kanye West's bodyguard to spy on Scott Disick before the two officially split up earlier this week and she may be planning to use whatever dirt he was able to uncover against the father of her three young children to gain primary custody of them.

RadarOnline reports bodyguard Pascal Duvier had been spying on Disick for a while prior to news of the couple's breakup after Kim and Kanye gave him permission to take orders from Kourtney.

"She tried the tactic of having Scott spied on before, but never over a sustained period of a time," said a source. "Kourt's done with Scott and upped the stakes to show him she means business."

Disick, 32, spent the Independence Day holiday weekend in Monte Carlo, France, where he was seen getting up close with rumored ex-girlfriend Chloe Bartoli while Kourtney remained home with their three children. The incident hardly marks the first time rumors of Disick being unfaithful to Kourtney over the life of their nine-year relationship have circulated.

Over the years, it's been reported he's been intimate with three of the sisters (Khloe, Kendall and Kylie) of the mother of his children. In one instance, it was rumored that he became so infatuated with Kendall he proposed to her and vowed to leave Kourtney and his children so the two could build a life together.

Since the split, Disick reportedly has been telling friends it was his decision to pull the plug on the relationship and is already rumored to have secured a new bachelor's residence for himself.

Despite now having to work as co-parents to 5-year-old Mason, 2-year-old Penelope and 6-month-old Reign, Kardashian and Disick reportedly have not spoken in days.

Duvier is also rumored to have previously worked for will.i.am and Fergie.