California Rep. Katie Hill — who’s been under fire for engaging in a “throuple” relationship with a former female campaign staffer — announced Sunday that she’s resigning from Congress.

“It is with a broken heart that today I announce my resignation from Congress,” Hill wrote in a statement she shared on Twitter.

“This is the hardest thing I have ever had to do, but I believe it is the best thing for my constituents, my community, and our country.”

The freshman lawmaker was also the target of a House Ethics Committee probe over allegations she was romantically involved with her current legislative director, Graham Kelly.

Hill, 32, had vehemently denied being involved with Kelly — which would be a violation of House rules — but did admit to a sexual relationship with former campaign staffer Morgan Desjardins, 24, while married to her now-estranged husband, Kenny Heslep.

The openly bisexual California Democrat told the National Review last week that she became involved with the campaign worker during the “final tumultuous years” of her abusive marriage to Heslep.

“I know that even a consensual relationship with a subordinate is inappropriate, but I still allowed it to happen despite my better judgment,” Hill said in a statement.

The pair’s relationship was first reported two weeks ago by conservative news outlet RedState, who backed up their claims by publishing a number of steamy photographs of Hill and her subordinate.

One photo showed the two embracing and locked in a kiss.

Another photo posted by the site showed a nude Hill brushing Desjardins’ hair.

Heslep apparently had no problem with his wife’s interest in Desjardins because he was a willing participant, according to reports.

Last week, The Daily Mail published a fresh round of scandalous photos – with one showing Hill holding a smoking bong and wearing what appeared to be a tattoo that looked like an Iron Cross on her bikini area.

In her resignation statement, Hill blasted Heslep and “hateful political operatives” for perpetrating what she called a “smear campaign built around cyber exploitation.”

“Having private photos of personal moments weaponized against me has been an appalling invasion of my privacy. It’s also illegal, and we are currently pursuing all of our available legal options,” she said.

Hill was a rising star in the Democratic party, a favorite of House Speaker Nancy Pelosi, who had been hand-picked for a coveted leadership seat.

Pelosi on Sunday night reacted to news of Hills’ departure, saying the freshman lawmaker “has acknowledged errors in judgment that made her continued service as a Member untenable.”

“Congresswoman Katie Hill came to Congress with a powerful commitment to her community and a bright vision for the future, and has made a great contribution as a leader of the Freshman Class,” Pelosi said.