Gerard Cassidy, a physical education instructor at MS137 America’s School of Heroes in Ozone Park, has been fired for having an “inappropriate relationship” with an ex-student and her mother, writes Susan Edelman at the New York Post.

The scandal broke in mid 2009 after the teen told her an aunt that “she had been secretly dating her ex-teacher,” says a report by the office of schools investigator Richard Condon.

She claimed to have had sex in his house “once or twice a week” without condoms.

“Mr. Cassidy told her he would marry her when she turned 18,” the aunt told investigators.

He “was very rich and would give her a house, a car, credit cards and security.”

This relationship continued despite Cassidy courting of the girl’s mom, who was recently out of an abusive relationship.

Cassidy is believed to have taken the teen and the mom to restaurants in Queens, together and separately, and has been accused of giving the teen alcohol, designer eyeglasses, Nike sneakers, a wool coat, a gold and diamond-chip accessory and an iPhone – as well as paying her phone bills for months.

The girl begged her aunt not to tell anyone, but the aunt told the teen’s father, who then subsequently informed the city’s Administration for Children’s Services.

According to city Department of Education documents and court records, Cassidy, 44, lost his $83,600-a-year job after 18 years in teaching, despite the recanting of the claim of sexual relations by the 16-year-old student.

Condon’s office obtained records showing that Cassidy called the girl’s cellphone 553 times between March and July 2009 and sent 383 text messages to her iPhone. About 125 calls occurred between 8 p.m. and 6 a.m.

In his Department of Education hearing, Cassidy claimed that it was left to him to motivate the girl into doing her homework and attend school.

The mother testified that Cassidy’s mentoring helped her daughter rocket to consistent A grades, insisted that she permitted Cassidy to call her daughter any time, but records have revealed that the student was still failing in her classes.

Hearing officer Douglas Abel upheld Cassidy’s termination. Cassidy appealed in Manhattan Supreme Court and lost, writes Edelman.