Only days after a Los Angeles court officially terminated his 13-month marriage to actress Joan Collins, Peter Holm is bravely picking up the pieces of his life.

The flaxen-haired 40-year-old ex-crooner from Sweden plans to write a book, and is looking for a publisher willing to help him tell his side of the love story that went awry.

"I don't think it will be much of a problem," said Joseph Singer, the New York literary and screen agent Holm has retained. "Their romance is a great story. Peter still has feelings for Joan. Their relationship is still very special to him. He wants to write an honest book."

Collins has described her fourth ex-husband as "a bit of a loser" and compared him in court to a household pet.

Singer signed up his new client after hearing him share his literary aspirations on the Phil Donahue show. The agent said yesterday that Holm, whom he has never met except by transatlantic telephone, "has a great business head. You get a feeling he knows what he's doing -- he was involved in Joan's book negotiations, you know. I was very impressed with the man."

Six publishing houses have expressed interest in the Holm property, Singer said, although he wouldn't name them or the price he has put on the book, which he called "substantial." A ghostwriter, whom he also declined to name, has just junked his previous project to take on the Holm epic.

Early reviews of the Holm book were mixed.

"I think he's a total {expletive}, but he's totally promotable," said Caroline O'Connell, whose Los Angeles public relations firm specializes in author tours. "He'd be a cinch to get on every local talk show in the country -- no problem. He'll say and do anything. He took TV crews on a tour of their house -- of the bedroom, no less."

"Personally," said Stuart Applebaum, vice president of Bantam Books, "I would look upon the opportunity to publish Peter Holm with the same perspective Peter Holm looked upon the opportunity to marry Joan Collins."

But Irving (Swifty) Lazar, the fabled bicoastal literary agent, declared: "There is no audience for that book, and a legitimate publisher wouldn't take it."

Singer said he wanted to cut the book deal for Holm as quickly as possible to take advantage of the publicity attending his divorce.

According to Singer, Holm is planning a media blitz in early October, when he returns from Europe for a court hearing to determine the financial settlement with his ex-wife, who is around 54. Holm has asked for $80,000 per month in living expenses, including $12,000 for "clothing and accessories."

But Lazar said it is already too late for the cleft-chinned Swede. "I don't think there are five people who care about him. It's over, you see. It's yesterday's news."