Eustace, a Bergen County Democrat who has served in the Legislature’s lower house since 2012, said Wednesday he’s “moving on to a different position” — though he declined to say what the job is.

“I’ve been honored and privileged to serve the people of New Jersey,” the 61-year-old Maywood resident said. “We’ve gotten some great stuff done.”

Politico New Jersey was the first to report the news.

Eustace was Maywood’s mayor from 2008 to 2011, when he was elected to represent north Jersey’s 38th legislative district — which includes parts of Bergen and Passaic counties — in the Assembly.

He is one of only two openly gay members of the Legislature. Assemblyman Reed Gusciora, D-Mercer, was the first. Gusciora came out in 2006, 10 years after his election.

Eustace and his late partner, Kevin Williams, gained national attention in the late 1980s when they became New Jersey’s first openly gay couple to apply to the state for joint adoption.

They later adopted three children who had contracted AIDS.

Eustace was elected to his fourth term in the Assembly in November.

But though he’s a major supporter of the environment, he was replaced as chairman of the Assembly’s environment committee in January.

That came after he backed former Assembly Speaker Vincent Prieto, D-Hudson, in the battle for who would be speaker as a new term rolled around in January. New Speaker Craig Coughlin, D-Middlesex, won out.

Eustace was also recently passed over for a state Senate seat when veteran Sen. Robert Gordon resigned to become a member of the state Board of Public Utilities.

Democratic committee members in the district are expected to vote Wednesday night for Eustace’s district mate, Assemblyman Joseph Lagana, D-Bergen, to fill Gordon’s seat instead.

Eustace denied that either of those developments played a role in his decision to step down from the Assembly.

“Hopefully, I’m a bigger man than that,” he said.

Eustace’s resignation means Democratic committee members in the district will also vote on someone to fill Eustace’s Assembly seat until a special election in November for the remaining year of his term.