I don't watch it myself but my hubby does - he said that the two characters were once married and the guy went missing and was presumed dead after 7 years so he is a bigamist.
They were married for 3 years and he left 27 years ago (at least that's what it sounded like, think Faye must have been young!). They went bust or something, he left and just never went back,she didn't know what had happened to him. He used to be called Daniel Lamb or something..