Three months after "Rehab Addict" star Nicole Curtis and ex Shane Maguire seemingly reached a truce in their long custody battle over son Harper, 3, the battle has taken a bitter new turn.

A July 8 report from The Blast reveals that Shane, a Michigan businessman, is now seeking sole custody of the toddler amid claims Nicole is an unfit parent.

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On July 3, Shane filed a request for custody in which he alleges that Nicole is "incapable of facilitating" a relationship between him and their son, according to documents obtained by The Blast. Nicole, he further claims, is "not a fit and proper person to share legal or physical custody of the minor."

According to Shane, when it come to their young son, the HGTV star wants to "ruin their relationship entirely" by turning custodial handoffs into a "game of cat and mouse."

He charges that drama on Father's Day forced him to involve his lawyer to make certain that he saw his son after Nicole, he claims, lied about where she was and, The Blast writes, "forced him to drive around town trying to locate the child."

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Though Nicole had not responded to the court filing at the time the story was published, she hinted at the drama in an emotional Independence Day Instagram post in which she shared with fans that she and Harper were not together for the holiday.

"My life has 2 sides -1. Where everything is funny & I can find humor in it all 2. Where my heart is so heavy with emotion it feels like it may burst. I did an interview today for the new season and was asked if I set out to be an advocate. No, I just set out to be a mom and moms protect their babies before anything else," she captioned a picture of herself holding her son in silhouette.

"To all the mommies facing this holiday without your babies -find your squad, let people in, there is no humor I offer to make it feel better -my heart aches with you. No child should ever have to choose...ever," she continued. "We weren't designed to be separated from our babies -that is, to every critic's dismay, scientific fact. God Bless and know you are not alone."

The home improvement star -- who also has an adult son, Ethan, from a previous relationship with Steven Cimini -- and the businessman have been battling over custody of Harper for years.

In 2016, though the court entered a final judgement regarding custody and financial support, The Blast reports -- Nicole was awarded primary physical custody while both she and Shane shared legal custody, and Shane was ordered to pay $1,200 a month in child support -- new drama soon flared up.

Earlier this year, Shane -- who's previously fought with Nicole over her choice to breastfeed their son until well into his toddler years (she was still nursing and co-sleeping as of March 2018, she told People magazine) as it interfered with their custody plan -- accused Nicole of moving from Michigan to California to prevent him from seeing this son.

Shane said she did this after he moved to Michigan from Minnesota, where they'd both lived when they were a couple, in order to be closer to Harper. In late March, they reached an agreement to split parenting between Los Angeles and Detroit.