Geoffrey Hendricks and Bici Forbes had been married for years and had two children when they faced up to a conundrum.

“By the time of our 10th wedding anniversary,” Mr. Hendricks recalled years later, “which is June 24, 1971, it was like: ‘Well, what should we do? Because we’re both gay.’ ”

Mr. Hendricks was an artist who was part of the boundary-stretching Fluxus movement, so it was perfectly in character when he and his wife, the artist now known as Nye Ffarrabas, decided to turn their disunion into performance art. On their 10th anniversary, they staged what has become known as the Flux Divorce in their Manhattan home.

“It was a public art ritual they created to symbolize an end of their marriage as it had been and the beginning of a new chapter that would include a non-monogamous, open relationship that made space for same-sex partners,” their daughter, Tyche Hendricks, said. “They strung barbed wire through the kitchen. They sawed their bed in half. They donned a pair of overcoats, sewed together back to back; then the women pulled my mother and the men pulled my father until the coats tore asunder.”

Mr. Hendricks died on May 12 at his home in Manhattan. He was 86 and had congestive heart failure and prostate cancer, his family said in announcing his death.

The Flux Divorce was just one of many adventurous artworks and art events he created or participated in during a career that also included teaching art at Rutgers University for 47 years.

Mr. Hendricks literally looked to the heavens for inspiration for some of his art; he was known for paintings of the sky, which he would render on traditional canvases and assorted other surfaces. (A fellow artist, Dick Higgins, gave him the nickname Cloudsmith.) But, like other Fluxus artists, he went far beyond the boundaries of painting.

The Fluxus movement, which emerged in the 1950s, defined art in terms of experiences as well as objects, and Mr. Hendricks was a fearless explorer in the art-as-performance world.

There was, for instance, another work that invoked his marriage, “Ring Piece” (1971), in which he perched atop a mound of dirt in the 69th Regiment Armory in Manhattan; embedded in the dirt was a box containing his wedding ring. “Ring Piece” was part of the eighth New York Avant Garde Festival, an annual testament to a reimagining of art. Other participants included John Lennon, who had musicians play a composition he called “Wind Peace,” in which fan-generated wind randomly turned the pages of the sheet music.

Another of Mr. Hendricks’s works was “Dream Event” (1972), which he described as “a 48-hour piece where I was fasting, sleeping and writing down dreams, naked on a mattress, under a sheet, with a pitcher of water to keep me from getting dehydrated and a pot to pee in, and where people could come in to observe at any hour of the day or night.”

And there were Mr. Hendricks’s headstands, which he performed all over the world — standing on his head for extended periods, perhaps painted blue or with signage dangling from his feet.

“I got to seeing a headstand as kind of a bonsai performance, sort of the minimum of performance,” he explained in an oral history recorded in 2016 for the Archives of American Art. “It was dealing with the least amount of space that you could work with, and it was just simply positing yourself in one place, and then reversing yourself.”

Mr. Hendricks was, in short, an experimentalist of the first order.

“The artists associated with Fluxus tended to lead bifurcated art-lives,” Barbara Moore, a historian of the movement, said by email, “on the one hand, creating unclassifiable objects and performances that continue to undermine expected gallery and institutional presentation; and on the other, producing works that can be exhibited in more traditional ways. Geoff encompassed this duality brilliantly.”

Geoffrey Hendricks was born on July 30, 1931, in Littleton, N.H. His parents, Walter and Flora Bishop Hendricks, were writers who traveled in intellectual circles; his father was an English professor who founded Marlboro College in Vermont and several other educational institutions.

Geoffrey attended the Putney School in Vermont and then enrolled at Amherst College, where he received a bachelor’s degree in 1953, when the Korean War was still in progress. Having been raised a Quaker, he applied for conscientious objector status and ended up doing alternative service teaching chronically ill patients at St. Barnabas Hospital in the Bronx. He pursued art studies at the same time at the Cooper Union, receiving his certificate there in 1956.

That year he joined the faculty at Douglass College, the women’s college at Rutgers University in New Jersey; he would later move to the university’s Mason Gross School of the Arts.

Rutgers, where the faculty already included Allan Kaprow, was becoming a center of avant-garde art, and Mr. Hendricks fit right in. It was, he said in a 2013 video interview for the Princeton University Art Museum, a time of “new ideas about what art is and the process of art making, and getting away from the idea of the painting and the object, to the experience.”

Mr. Hendricks, who received a master’s degree at Columbia University in 1962, could make traditional art worthy of a gallery showing (the first solo exhibition of his sky paintings was in 1966 at the Bianchini Gallery in New York), but he could also turn expectations on their head, much like one of his signature headstands.

“His lusciously painted depictions of sky looked beautiful as canvases isolated on a wall, as fabric hangings, incorporated into installations, covering clothing or a Volkswagen Beetle,” Ms. Moore said. His satirical “Picnic Garbage Placemat,” she said — basically a photograph of garbage in the dimensions of a place mat — “was a genuinely utilitarian object upended with an image not normally fit to grace a table.”

Mr. Hendricks married Ms. Forbes in 1961; they had known each other since they were students at Putney.

After their divorce (which occurred officially a few months after the Flux Divorce) Mr. Hendricks was in a relationship with the artist Brian Buczak, who died in 1987; Alice Neel painted their portrait in 1978.