Democratic Senate hopeful Graham Platner used to spout bizarre fantasies about raping home-invaders — and he would do it while watching television and sharpening an axe, according to an ex-girlfriend.

“He said this a lot: If anybody ever broke in here, I would rape them,” said 40-year-old Lyndsey Fifield, who dated the Maine candidate from 2013 to 2015.

“He was like, ‘I would rape them to show them that I’m dominant,’” she told the New York Times, adding Platner would clarify that he wouldn’t be raping the hypothetical intruders in “a sexual way, not in a gay way.”

Those are just the latest claims to rock Platner’s campaign since he announced a run to take on longtime Republican incumbent Sen. Susan Collins in August, with a slew of vile online comments that he made disparaging women, rape victims, minorities, police and veterans emerging in October.

He was also found to have a Nazi “death’s head” tattoo on his chest that he got while in the Marines, and was exposed just last weekend for texting women on a hookup app while he was married.

And on Thursday Fifield became one of three ex-girlfriend’s to tell the Times that all of that behavior matched what they saw when dating Platner over the years.

Fifield claimed Platner’s talk about rape would leave her unsettled — with the feeling amplified by the assault rifle he would often leave lying around his apartment, and the sharp forestry axe he would hone while he watched TV and spouted the bizarrely violent thoughts.

He would even talk about killing people he considered a threat, and how rape was an act of power, Fifield said.

Those claims were just a handful of the alarming accounts Fifield and two other of Platner’s ex-girlfriends told about him, with others describing him as regularly unfaithful and contemptuous of women — and perfectly aware of the Nazi tattoo he sported, despite later publicly insisting he had no idea what it was.

Fifield even claimed he would sometimes grab her by the shoulders during arguments — hard enough to leave marks — and once twisted her arm before pushing her into a room and blocking her from getting out.

Platner “strongly” disputed Fifield’s accounts of physical fights, but admitted some of his behavior may have been questionable at the time — citing PTSD he was enduring from his combat as a Marine in Afghanistan.

“I’ve been open about what was a very dark period of my life where I struggled with undiagnosed PTSD, too often self medicated with alcohol, and was a far from perfect boyfriend,” he told The Post in a statement.

“I take responsibility for all of that, and wish I had been better. Any characterization beyond that is false, and I believe, politically motivated,” he added. “Let’s be very clear: This is a lifelong GOP operative who’s dedicated her career to electing Republicans.”

Fifield — who has spent time working on Republican campaigns — insisted she would have told her account of dating Platner no matter what party he was running for.