She later met and fell in love with a former Zygon warlord named Trevor, or Haygoth. They met at the Kendal Folk Festival in 1979. Trevor gave Pat a necklace, which fused to her flesh, that was actually a Zygon device he wished to keep from the other Zygons. She and Trevor also got married.
Lucie and the Doctor met Pat again in 1984, and discovered that her husband was a Zygon. She was killed by Trevor's former warriors, but unknown to Lucie, her husband decided to keep her shape to honour her. The Auntie Pat that Lucie grew up with was actually Haygoth. (AUDIO: The Zygon Who Fell to Earth)