Rumer Willis has accused Derek Richard Thomas of "insane emotional abuse".
The House Bunny actress - who split from the musician in August 2024 after two years together - has submitted a declaration to the court opposing her former partner's request for a child custody order in relation to their three-year-old daughter Louetta, and in the documents she detailed his alleged abusive behaviour.
According to People magazine, Rumer told how Derek had shown a "persistent pattern" of "insane emotional abuse" since they separated, which she alleged was "often in front of the minor child or while they were trapped in the car with him."
The 37-year-old star claimed her former partner has engaged in "ongoing coercive control through prolonged circular verbal attacks that he is unable or unwilling to stop."
Rumer alleged Derek had engaged in such behaviour for "over six hours at a time on what became a daily basis", and claimed his "erratic and bizarrre" conduct "escalated" after Louetta was born.
In her filing, in which she is seeking primary custody of the youngster, she wrote: "I was constantly trying to keep the peace and walk on eggshells.
"He wanted to isolate me from my friends and family.
"He constantly called me a liar with no reason behind it. He told me I was a bad girlfriend all the time."
Rumer told how Derek allegedly showed "paranoid behaviour" and was convinced she and her mom Demi Moore were "plotting" to take Louetta away from him.
She wrote: "For a long time, it was difficult for me to stand up to [Thomas] as I tried to avoid his emotional tirades and abuse even for a long time after he moved out."
She explained she doesn't want her former partner to have "overnights or time with Louetta" without an Evidence Code Section 730 child custody evaluation because the tot has been left "traumatised" and "crying a lot" as a result of his alleged behaviour.
In addition, Rumer raised an objection to Derek's current fiancee, Lizzie Loch, being present during his custodial time because of his alleged "history of fighting in relationships, and in front of the child."
But Derek has hit back in his own declaration, insisting Rumer has only made the request because she is "enraged" by Louetta's "clear affection" for his new partner.
While he denied the abuse claims, he admitted his relationship with Rumer was "unhealthy".
He wrote: "I have committed no acts of domestic violence in any form, including any active coercive control. [Our] relationship was unhealthy and appropriately came to an end, but it was not all characterised by any violence, physical or emotional attacks or intimidation on my part.
"The decision to end the relationship between myself and [Rumer] was a mutual decision made in our mutual best interests."
Derek also pushed back on a request from his ex-girlfriend that he submit to court-ordered drug testing beccause of his alleged "chronic daily marijuana use and evidence of behaviour indicative of someone under the influence of drugs for extended periods of time."
He insisted he is not a "current user of marijuana", though he used to "as legally allowed", but never to the extent that he was "unable to fully and properly fulfill my duties and obligations as Louetta's father."
However, Rumer had alleged he was once so high he couldn't "even watch [Louetta] for those couple of minutes without her rolling off the couch" and that the toddler had "fallen off the bed once" in November 2023, and Derek "then made it all about him that I was upset about him letting her fall off the bed instead of just comforting her baby and helping her feel better."
But Derek insisted Louetta has "never suffered for any want in my care, has never been injured in any way, has not suffered trauma or emotional or physical abuse of any kind nor been neglected at any time she's been in my care. [Rumer] fails to detail, even a single credible instance of any mistreatment or neglect by me."
Rumer accused her former partner of causing "high stress and chaos" when she visited her "extremely ill" dad Bruce Willis, who has frontotemporal dementia, and alleged he hasn't paid her "any support" because he expects her "wealthy family to take care of everything."
But Rumer warned she is "going to be in severe debt with attorney fees" because she doesn't rely on her parents for money.
Demi, 63, backed up her daughter's claims with her own declaration, in which she said she had witnessed "aggressive" behaviour from the musician when Rumer gave birth at home.
She wrote: "[Thomas] had no consideration to Rumer, the baby, the process or anyone else for that matter. He essentially ruined what should've been one of the happiest moments of [Rumer's] life."
