It only becomes someone else's business when that person tells someone else about it. Then they open themselves up to all kinds of opinions and gossip. If a person is going to commit adultery then they should keep it to themselves. Unless they just don't care.
Is your friend or coworker's adultery your business? Is anyone other than your own adultery your business?
Dear Jan Nicka,
That is known as DRAMA, and I don't want to be involved...
I would simply move on, spending my time elsewhere.
Given the nature of adultery---a breach of at least generally agreed upon standards of social behavior---it's highly likely to affect a number of people beyond those "intimately" involved (pun intended).
So if I start a fire close to you, who's responsible for making sure you are far enough away to not be affected by the heat---you or me?
Bottom line---if it affects me, it's my business also.
But I may just choose to move away from the fire, rather than try to extinguish the fire---unless it's too close to my house in the first place.
No one else's business is my own, I have enough of my own business.
Generally ... None of my business.
HOWEVER - if it involves someone in a management position above me, it becomes my business simply due to possible favoritism ... Or making a "hostile workplace" if it ends badly, or the parties having an argument.
Rooster's right. Adultery is best kept to the parties concerned. I'm not into gossip and I really don't want to hear about somebody's betrayal.
Not unless they make it your business. If they insist on talking about it and it makes you feel uncomfortable then say so, If someone you knew were the victim of this infidelity then you'd have to ask yourself if you would want someone to tell you if you were the one being hurt by this.