Well here's a zany take on it for a bit of fun...
A marriage is a contract that is governed by the Commonwealth Marriage Act.
The Marriage Act defines "marriage" as "the union of 2 people to the exclusion of all others, voluntarily entered into for life."
Therefore anyone who has sex with another person while still married, can be sued for breach of contract!
Scruff
Can that really happen? How come Tony Danos the lawyer mention that?