Ailsa Stewart (nee O'Rourke, previously Hogan) is a fictional character from the Australian soap opera Home and Away. She was married to Alf Stewart and had a son Duncan. She was played by actress Judy Nunn for 13 and a half years. When Nunn left the show she was one of only four original cast members. The role of Ailsa was briefly played by theatre star Nancye Hayes whilst Nunn was taking leave due to illness in 2000.

Who was alf married to in home and away? OK. Let's think. My stream of consciousness:
The relevant sentence in the passage is: She was married to Alf Stewart and had a son Duncan. The answer is Ailsa Stewart.