I worked with a married couple many years back. Then they had a kid. So they split their shifts since daycare costs to damn much for 2 Perkins cooks. So they very little of each other. So they went to an open relationship model because "needs". One of the male managers known for hitting in and fucking all waitresses (because he controlled their schedule...) took the opportunity to start plowing her too. The husband... Thought he had game and thought he could get someone at work. He couldn't. So that had to be a fun dynamic. The husband and wife's manager working side by side with both of them and the manager was having a baby with one of his other conquests that also work there. Their marriage quickly fell apart and people's opinion of her and the manager and the husband took a leap off a cliff. Before all of that they were a very happy couple and great friends to be with. Afterwards they were all insufferable and the child pays for all this.
Knew another couple, married, with for kids. They moved to a open relationship model... Probably for plethora of reasons, Part of me believes that she misses her early twenties party girl that she used to be. Turns out being in mid-30s and having four kids and being married really limits the type of guys that you get. Her former husband moved on with life. And she now has a fifth kid with someone that was a temp boyfriend.