A man who paid a surrogate to have his baby became overwhelmed when he learned she was having triplets — and demanded the woman abort one of the fetuses while threatening her with financial ruin, she claims.

“They are human beings. I bonded with these kids. This is just not right,” mom-to-be Melissa Cook told The Post on Tuesday.

Cook’s heart-wrenching dilemma comes as Gov. Andrew Cuomo and state lawmakers are weighing whether New York should lift its ban on commercial surrogacy, which was enacted in 1993.

The babies’ dad, a Georgia man, hired Cook for $33,000 to have a child by in-vitro fertilization using his sperm and the eggs of a 20-year-old donor.

The California woman was implanted with three embryos, which defied the odds to all go on to develop normally.

Cook, 47, said she and the man learned she was having triplets when the embryos were around 8 or 9 weeks. He almost immediately began to raise concerns, and they have grown increasingly threatening, she said.

Cook, a mother of four — including her own set of triplets — is now 17 weeks pregnant.

She also had a fifth child as a surrogate.

California law says that aside from life-threatening exceptions, fetuses can’t be aborted once they become “viable,’’ or around 20 weeks.

The dad “understands, albeit does not agree, with your decision not to reduce,” his lawyer, Robert Warmsley, wrote in a Friday letter to Cook, who has never met the sperm donor.

“As you know, his remedies where you refuse to abide by the terms of the agreement, are immense [and] include, but are not limited to, loss of all benefits under the agreement, damages in relation to future care of the children [and] medical costs associated with any extraordinary care the children may need,” the lawyer warned.

Cook received another letter from Warmsley on Tuesday urging her to schedule a “selection reduction” — abortion of one of the fetuses — by day’s end.

A day earlier, Cook argued in an emotional letter to the dad, “The doctor put in three healthy embryos . . . The chances were high they were all going to take. You knew I was 47 years old. If you knew you only wanted two babies, then why put in three embryos?”

According to her contract, Cook is entitled to her $33,000 pregnancy fee for one baby, plus an additional $6,000 for each additional child.

Given the pressure she’s under, Cook said Tuesday that she was wavering on her decision to keep all three babies.

“I have to reduce. I’m scared. I don’t want to suffer,” said Cook, who is split from her husband and lives in Woodland Hills, Calif.

Jennifer Lahl, head of the Center for Bioethics and Culture, a group that opposes surrogacy, said the Cook case is the first she’s aware of in which a surrogate mom has gone public to expose the pressure she’s under to undergo an abortion.

“Why on earth would Cuomo want to set up a system like this in New York? It’s parent breeding,” said Lahl, who is seeking to help Cook.

At least 22 states allow surrogacy fee arrangements.

Warmsley, the dad’s lawyer, declined comment.