I'm planning to listen to their argument by standing outside the closed door.
Why are you going to spy on them like that?
I heard her blaming me for all of our problems
Spying on people is wrong and you should mind your own business. If you have an issue you should talk to them about it.
Who cares, I'm busy enough to spy on them.
It doesn't matter how much time you have, spying on people is an invasion of their privacy and you shouldn't do it. How would you feel if you found out someone was listening in on your personal conversations?