Rosamunde Pilcher: Möwen im Wind (1999)

Dr. David Douglas is about to start his own private clinic and marry architect Jane Merchenson. Then his father dies, leaving debts from a real estate fraud he fell victim to, so selling the mortgaged Cornish family estate Oaktree isn't nearly enough. David cancels the wedding and sells to John Tyson, a friend of Jane's father Michael, who starts renovating it, employing her. Later David discovers Jane gave birth to their son, Nicky, without telling him.