Quackity has just come back from work and he was very tired, so he decided to go to his bedroom and see if his husband Thanos is there.
When he walked in he saw Thanos and Shrek making out, Quackity was so heartbroken that he got a gun and shot them both.
The poor heartbroken guy then packed his bags and left the house.
He decided that he should start a new life.
