The relationship between Siobhan and Andrew was once filled with love and compassion, but Siobhan began to change, causing the two to drift apart. Siobhan even had an affair behind Andrew's back with their mutual friend, Henry Butler,the husband of Gemma,that resulted in Siobhan getting pregnant.
Siobhan is also the stepmother of Andrew's daughter, Juliet Martin, with whom she has a terrible relationship with.
- See also: Shivette and Andrew
After Shivette entered Andrew's life (unknowingly by Andrew), he was pleased to find that Siobhan was returning to the pleasant, friendly and lovingly Siobhan he first fell in love with - this was actually Bridget taking over Siobhan's life.
Andrew and Siobhan have not been seen together since the switch.