Nobody Wins
Infidelity has to be the worst thing ever. If it doesn’t tear families apart, it leaves them a shell of their former selves. Or, and this is the worst-case scenario, the other spouse has no idea what’s going on and continues to live as if nothing is happening behind the scenes.
The OP’s father is the scumbag in this story, and so is their boss’ wife. You see, the dad is shacking up with their kid’s boss’ wife, and his wife, as well as the boss, has no idea what’s going on behind closed doors. The most heartbreaking part of this story is that the mother, according to the OP, is the best mom ever. You suck, dad.