FOR a woman whose husband once knowingly sent her dead roses, Angela Koch’s Valentine’s Day was particularly sweet: a $16 million divorce payout, courtesy of the same man.

Multimillion-dollar oil baron Bill Koch ponied up the whopping settlement last week, closing the final chapter on one of Palm Beach’s most tempestuous marriages.

“It’s the best present I’ve gotten in years,” said Angela, who filed to end their four-year union last year, shortly after Bill allegedly threatened to beat her with a belt during a fight at their Cape Cod vacation home. He was arrested and charged with domestic assault and battery and with threatening to commit murder.

As well as the money, Angela received millions more in jewelry, furniture and art, plus $22,000 a month in child support for the couple’s two kids, William, 3, and Robin, 1 1/2.

“It’s a happy day, particularly considering how it could have played out,” said the woman who was once a gift officer for Tulane University Medical School in New Orleans.

Koch’s swift kiss-off to his wife could well be considered a record for a man who has a history of getting stuck in drawn-out litigation.

In the 1980s, he sued his own mother over her allocation of a family trust, and, in 1998, lost a 17-year court battle with his brothers, Charles and David, over their buyout of his stake in the family oil business.

Koch was also embroiled in a three-year palimony battle with a former mistress, Catherine de Castelbajac.

Angela Koch filed for divorce in September, two months after the Cape Cod blowout. The couple briefly considered a reconciliation for the sake of the children, and even met for therapy, but after Angela discovered that her husband had hired a private eye to tail her, it was all over.

“It was frightening, and embarrassing,” she told The Post. “At that point, I knew there was no hope of reconciling. I had become the enemy.”

Initially, it appeared Bill, 61, head of the energy firm Oxbow and worth $650 million, was gearing up for yet another protracted legal battle over the divorce.

“He told us he would try to have the prenup set aside,” said Jeff Fisher, the high-profile Palm Beach divorce lawyer who represents Angela. “He told her, ‘I’ll litigate you into the ground.'”

Then, Angela asked a Connecticut court to unseal a 1996 file about Bill and his first wife, Joan Granlund, claiming it could contain evidence of prior domestic violence.

Suddenly, Bill agreed to settle, and she dropped the abuse charges.

AN UNPRETENTIOUS, stunning blond with dazzling green-blue eyes and a lovely Southern drawl, Angela Browder Gauntt was recently divorced from her first husband and living in New Orleans when a mutual pal suggested she meet Bill Koch in 1995.

Tall, dashing and flamboyant, the white-haired Koch was still basking in the glow of his 1992 America’s Cup yachting triumph.

“You’d think I’d have known who he was, but I didn’t,” Angela recalled.

Within the week, he had turned up at her door – with an America’s Cup scarf as a gift – and on their first date, at New Orleans’ swanky Commander’s Palace, Koch was “fun, gentlemanly and charming,” Angela said.

He sent flowers the next day, but the pair saw each other just “one or two times” during the next nine months.

At the time, Bill was duking it out with De Castelbajac, and another ex-girlfriend, Marie Beard, was pregnant with his daughter Charlotte, now 4.

Then, in May 1996 – after only five dates – Koch proposed. They married that November.

“I have this thing I call ‘stray-dog syndrome’ – I think I can bring ’em home and fix ’em up,” Angela said. “He had a lot of problems, but I was very much in love and thought we could build a good life. He’d already been down the road with the bimbos, and said he wanted to have a real family.”

Oddly, the couple didn’t live together until a month after the wedding, because Angela’s daughters had to finish their school term before moving to Palm Beach.

And there was no honeymoon – the day after the wedding, Bill went on a hunting trip with his buddies.

“I guess it was strange, but, at the time, I was so busy I didn’t mind,” she said.

Then, a few months later, Angela was pregnant.

“William’s birth was one of the great moments of our marriage,” she said. “I felt it was going to be a real bond between Bill and me.”

BUT, by the time daughter Robin came along, Angela’s hopes were lower. Bill was always traveling and “I’d realized I was going to be the parent,” she said.

Still, the family took lavish vacations together, and, in 1998, Koch built a $30 million, 30,000-square-foot home on ritzy Ocean Boulevard.

That same year, Koch lost his lawsuit against his brothers.

“He was devastated,” Angela said. “It was something he could not get over – it just ate him up. After that, everything just took a turn for the worse. He was depressed and despondent.”

In court papers, Angela claimed Bill has an alcohol problem. Koch, who owns a $9 million wine collection, denies this, but Palm Beach sources say he’d talked openly about checking into rehab last summer.

“He was not fun to be around when he drank too much,” Angela said.

Although well-liked in town, Angela isn’t a social-circuit regular.

“She’s sociable, certainly, and I’ve seen her at a few parties, but she’s not a socialite,” said Shannon Donnelly, society chronicler for the Palm Beach Daily News.

“She’s basically a mom who’s involved in school, church and a few select charities. Everyone who knows her is crazy about her.”

Last week, Angela and the kids left their Ocean Boulevard home and moved down the road to a smaller, 7-bedroom home. It cost $5.3 million of her new bounty.

Bill is back in his mansion, his social life in full swing. Palm Beachers say former flame Marie Beard has told pals she will live in the “big house” with him, but he’s reportedly romancing socialite Barbara Chevellard.

Locals say she and Beard had a nasty set-to recently, when both of them showed up at the same time at a Palm Beach beauty parlor.

Rumor also has it that Angela had planned to play house with Palm Beach Police Chief Frank Croft after her settlement, but she’s quick to deny this.

Although the two dated, it was never a hot romance she said, adding, “Anyway, I have children – I would never live with someone.”

The newly minted millionairess is, however, dating Carlos Arruza, of the wealthy Fanjul sugar clan, but “he’s not moving in, either,” she said, and laughed.