A fraudster who gave his fiancée a false name, neglected to mention he had a wife and children and lied about having a vasectomy has been jailed for six years.
Greg Wilson, 39, told Coleen Greenwood he was a firefighter called James Scott, Newcastle Crown Court heard.
Wilson, of Lingwood Court, Thornaby, admitted £100,000 of fraud.
Miss Greenwood said she was devastated to discover her plans for the future were "built on deceit and lies".
Wilson had told her he had had a vasectomy, showing her a fake document he claimed was proof of the procedure, and she later got pregnant, the court heard.
Wilson admitted making a false statement by naming himself as James Scott on his son's birth certificate.
In a victim impact statement read out in court Miss Greenwood said: "Our child's birth certificate has a father's name that never existed and I've found no way of changing it.
"The shock, hurt and disbelief I've felt from this day is extremely hard to put into words - it felt like it was happening to someone else."
Wilson had told her he had rescued a boy from a burning building, breaking his back in the process, and showed her fake texts and a card from the grateful family.
He used fictional fire service shift patterns to explain why he had to be away for periods in the week, when in fact he had a second life with his family. He twice cancelled his wedding to Miss Greenwood at Wynyard Hall.
The court heard Wilson persuaded his fiancée and her sister to invest £58,000 in a fake property company, falsely claiming Sunderland footballers Jack Rodwell and Vito Manone were clients.
He also forged bank statements to convince estate agents he was a cash buyer for a £1.5m house on Durham's Ramside Park Estate but he had "no means whatsoever" to pay for it.
Newcastle Falcons rugby club were left £9,000 out of pocket after he joined their platinum club in the name of James Scott but made no payments.
When caught out in his deception Wilson handed Miss Greenwood their baby son through an open window in his car, drove off, and never returned.
Judge James Adkin said the "sophisticated fraud had caused huge damage".
It was an "extraordinary case with a litany of fraudulent activity" that showed "jaw-dropping arrogance and cruelty", he said.