“When I was 20, I thought I knew how things worked: desire, intimacy, beauty,” director Adina Pintilie, 38, tells The Post. But “reality is much more complex.”

Her film “Touch Me Not,” screening at MoMA Friday through Jan. 17, is an unflinching look at human sexuality, replete with nudity and a possibly unprecedented inclusion of disabled cast members, one of whom, Christian Bayerlein, is partially paralyzed.

A blend of fact and fiction shot over seven years, “Touch Me Not” won the top-prize Golden Bear award at 2018’s Berlin Film Festival. It’s a labor of love that is, at its core, about love.

“Our bodies and our sexuality are such essential aspects of our life, yet they’re topics we find it so difficult to talk about,” says Pintilie.

Its main character, played by British actress Laura Benson, embodies the title: Filled with repressed anger, she finds it impossible to be physically close to anyone.

‘Our bodies and our sexuality are such essential aspects of our life, yet they’re topics we find it so difficult to talk about.’

But it’s a non-actor, Bayerlein — a disability-rights activist with spinal muscular atrophy — who, with his radical honesty, steals the show. Pintilie found him through an extensive search for people with unconventional sex lives.

“He’s a fascinating personality,” says Pintilie. “He told me that I’m going to get attacked for exploiting people with disabilities . . .

“He said, ‘Look, [people] have their own preconceived notions about disability. They think we just need to be taken care of and that we have no sexual life. We have the same desires and the same right to be sexual beings as anybody else.’ ”

Bayerlein and his real-life, able-bodied girlfriend, Grit Uhlemann, are shown in deep conversation about intimacy and, at one point, entwined at a strobe-lit sex club. Pintilie says one of the things the film changed for her was her own concept of their relationship.

“There are many moments when Grit is very vulnerable and he’s the powerful one. She says, ‘I feel held in Christian’s arms.’ The harmony in their relationship is something I have rarely seen in so-called normative couples.”

Pintilie, Bayerlein and others will host a free discussion of the film Saturday at 3 p.m., with Q&A’s following Friday and Saturday’s 6:30 p.m. ticketed screenings. MoMA.org.