After getting suddenly married to Gus in season 5, Fiona finds herself in a pickle because Jimmy come back into town. She sleeps with Jimmy one night and feels bad enough to tell Gus. He immediately falls into the differentiating stage because he is annoyed with Fiona’s behavior. Their relationship falls into the circumscribing stage when they stop putting in effort to communicate with each other. They don’t really go through a stagnating stage because they both know what is coming, so they go straight to the avoidance stage; only seeing each other on the streets or when unexpected/unplanned. Gus and Fiona’s relationship enters the termination stage when they file for divorce. The relationship goes through these stages rather quickly, and they get back to their normal lives almost immediately after.