NEW YORK >> Jurors at Harvey Weinstein ‘s sex crimes retrial heard Monday from a woman who said her consensual relationship with the ex-movie mogul descended into rape.

At times, “he validated me so much,” Jessica Mann said, but when he was told no, “the monster side would come out.”

Mann is the last of three accusers to testify in the case, and the one with arguably the most complicated history with Weinstein. The 73-year-old has pleaded not guilty to all the charges and maintains he never sexually assaulted or raped anyone.

Mann, a cosmetologist and hairstylist, said she met Weinstein at a party in late 2012 or early 2013, when she was 27 and had recently moved to Los Angeles to try to launch an acting career.

She said he took an interest in her ambitions, and they had a few follow-up meetings that alternated between professional talk and boundary-pushing, particularly a request for a massage that Mann said she reluctantly gave the ex-studio boss. Weinstein invited her to an Oscars bash that Mann, new to Hollywood glitz, attended in her high-school prom dress.

She said she wasn’t attracted to Weinstein and initially refused his first sexual advance, but eventually succumbed to him performing oral sex because Weinstein said he wouldn’t let her leave until she let him “do something.” Although she felt confused and “defiled,” she then agreed to consensual encounters with the then-married man, she said.

Partly, she worried about the professional consequences of alienating a powerful producer who had just dangled the prospect of movie roles. She also recalled thinking that “if I was in a relationship, maybe it would feel different,” and that “maybe he did like me.”

“I just thought that maybe it would take the pain away,” said Mann, 39.

In March 2013, she traveled to New York with a friend. After the pals made plans for breakfast with Weinstein, he showed up early and got a room at Mann’s hotel, over her protests, she said.

Weeping and wiping her eyes on the witness stand, she said she went upstairs with Weinstein to try to avoid a public argument and told him, “I don’t want to do this,” but he shoved the door shut as she tried to leave.

After Weinstein demanded she undress and grabbed her arms, she said, she “just gave up.” Mann said he then had sex with her — after, she believes, injecting himself with an erection-promoting drug that she later found in the bathroom trash.

As she spoke, Weinstein quietly consulted one of his lawyers, then looked ahead of him at the judge’s bench.

Mann told no one about the alleged rape. She said Monday that she doubted she’d be believed and feared reprisals from the well-connected Weinstein.

Over the ensuing months, she nudged him about a potential movie part — he arranged an audition, which went nowhere — and told him she appreciated “all you do for me,” according to emails shown to jurors. She also sent him her new phone number, relayed a compliment she’d heard about him, and asked whether he’d be in Los Angeles for her birthday.