A pair of professional dancers filed a lawsuit on Wednesday accusing a former dance teacher of sexually assaulting and abusing them, and accusing his wife — an internet-famous ballerina who has danced with the Boston Ballet — of participating in some of that abuse.

The former teacher — who has been known by several names, but is called Mitchell Taylor Button in the suit — is married to Dusty Button, who was a principal dancer with the Boston Ballet and who has amassed more than 300,000 Instagram followers and several corporate sponsorships with viral photos and videos of her dancing.

The suit, filed in United States District Court in Nevada, claims that “the Buttons abuse their positions of power and prestige in the dance community to garner the loyalty and trust of young dancers” and said that the couple would “exploit those relationships to coerce sexual acts by means of force and fraud.” Mr. Button is a defendant in the lawsuit; Ms. Button is not, but is described as a “non-party co-conspirator.” A lawyer for the couple said that they denied the charges.

The suit asserts that one of the plaintiffs, Sage Humphries, now a dancer with the Boston Ballet, met the Buttons in 2016 when she was in the company’s apprenticeship program and that the couple sexually and verbally abused her, forced her to live with them and isolated her from her family.

“They had control over my phone and passwords to my Instagram, my email,” Ms. Humphries, now 23, said in an interview. “They had complete control over me. If I wanted to do anything, I had to ask them first.”

A second plaintiff in the lawsuit, Gina Menichino, alleges that several years earlier, Mr. Button sexually assaulted her when she was 13 years old and he was her 25-year-old dance instructor in Florida.

The lawsuit says that Mr. Button used several names, including Mitchell Moore, Taylor Moore and Mitchell Button.

A statement sent through a lawyer who is speaking for the couple, Ken Swartz, said, “Taylor and Dusty Button categorically deny these baseless claims and they look forward to the opportunity through court proceedings to disprove all of the plaintiffs’ false and fraudulent allegations.”

According to the lawsuit, Ms. Menichino, now 25, said that she met Mr. Button when she was a student at a Centerstage Dance Academy in Tampa, Fla., where she knew him as Taylor Moore. On two occasions in 2010, the suit says, she and Mr. Button were sharing a blanket while watching a movie with other dancers from the studio when Mr. Button sexually assaulted her.

Mr. Button regularly sent sexually explicit text messages, photos and videos to Ms. Menichino, the lawsuit said, and solicited the same from her. Ms. Menichino had aspirations of becoming a professional dancer, it said, and Mr. Button would reward her “compliance” with special dance opportunities, such as assistant teaching at a dance convention.

“The whole game was to keep him happy,” she said in an interview. “Don’t get him angry, or I was unworthy and I would lose my dance career.”

Ms. Menichino, now a dancer, teacher and choreographer, said in an interview that she had reported her experiences to the police in 2018 but that they told her they had found insufficient evidence to pursue a criminal case. According to police records provided by the plaintiffs’ lawyer, another dancer from the same Tampa studio reported to police in 2012 that Mr. Button had sexually assaulted her numerous times, some of them at her home; that case did not result in criminal charges, either, in part because of a lack of supporting physical evidence, the records said.

Ms. Menichino’s mother said in an interview that her daughter told her there had been “inappropriate interactions” involving her and Mr. Button after he had left the studio job.

In Ms. Humphries’s case, her mother and father said in an interview that they had sensed something was wrong with their daughter’s living situation and had flown to Boston to “rescue” her.

Ms. Humphries said in an interview that she had been in awe of Ms. Button, who was a principal dancer with Boston Ballet, and started spending concentrated amounts of time with her and her husband in 2017. But their behavior toward her became increasingly controlling, the lawsuit said.

According to the court filing, the couple insisted that Ms. Humphries sleep at their apartment regularly and eventually forced her to live there full-time and paid for her meals and personal expenses; Mr. Button told her that if he had access to her social media account, he could “make her famous like Dusty.”

“If Sage ever attempted to distance herself or disobey the Buttons,” the lawsuit said, “they would threaten to revoke their financial support and sabotage her career.”

One evening, Mr. Button sexually assaulted Ms. Humphries in his apartment, the lawsuit said, starting a pattern of sexual abuse that sometimes included violent sex acts that she did not consent to. The filing said that on several occasions Ms. Button held her down to immobilize her while Mr. Button had sex with her. And at one point, the suit says, the husband and wife got into a physical altercation that ended with him “striking Dusty across the face” because he was angry that she had had sex with Ms. Humphries.

In August 2017, Ms. Humphries, then 19, received abuse protection orders against both Ms. Button and Mr. Button, the lawsuit said.

The Boston Ballet said in a statement on Thursday that Ms. Button’s employment had been terminated in May of 2017 but declined to say why.

“Boston Ballet supports Sage Humphries who is bravely coming forward, sharing her experience to protect others, and seeking accountability and justice,” the company said in a statement.

Sigrid McCawley, a lawyer representing the two plaintiffs, said that there is a trend of predation in the dance world because of ingrained power dynamics and the desire on the part of dancers to gain approval from authority figures.

“Grooming in that environment is particularly easy for a perpetrator,” she said, “because he has full access to very young victims for long periods of time.”

Kitty Bennett contributed reporting.