It's wrong based on consent.

If one party in the married pair – who consented to be with each other forever, usually in front of many others – defies that consensual agreement, then what they did is wrong.

Otherwise you can just use a thought-terminating cliche like "all rules / words / ideas are made up" and end any meaningful discourse.

I’m in a married, committed relationship with my partner because that is how we both decided this is the kind of relationship we want.

We also have friends who are married but see other people openly, and both parties are aware, and their additional partners know that they are married.

Neither one is right or wrong, it’s what works for them.

In this case, both people went into their marriage with the intent to remain monogamous. These two did not honor that. That is why is wrong - it’s not about seeing other people if that is the initial agreement. It’s the lie, which both of them did.

Orgies still happen. Open relationships, too.

If you don't want to be exclusive then don't enter into an exclusive relationship.

I agree we could be less uptight about open relationships, but this is really about a rich filthy person being humiliated at a time when most of us feel powerless to stand up to money in any real capacity.

You're only thinking of the morality side of it.

It's also wrong because they work for a company that probably says subordinate-supervisory relationships are forbidden because of the power imbalance and complications around how a personal relationship--or even the perceptions of one-- might affect workplace decisions--to say nothing of the invitation of harassment lawsuits. Co-workers--even non-supervisory-- who might even be at the same "level" or their work brings them together for anything can be incredibly problematic. All of this is even at a local, department or site level to say nothing of C-level consequences. This also says nothing of the fact that one of them is in charge of the function, HR, who would be the person most responsible for ensuring this kind of conduct didn't happen between employees. The hypocrisy and abdication of duty couldn't be more severe. Both have lost all credibility with anyone in their company, which means they cannot lead others.

CONSENT

During roman times, it was common with complete orgies.

oh fam thank you... I needed a good laugh...

Why did the Romans construct so many buildings? for their ORGIES

Why did the Romans build acqueducts? to clean up after the ORGIES

Why did the Romans make their roads? to get to their ORGIES

Why did the Romans conquer so many people? because they needed folks for their ORGIES

thank you, friend. fwiw you're kinda right about morality being a social construct, but I don't know if that's the best takeaway from all this.

I think a lot of this stuff happens all the time.

sure. and people get caught cheating all the time. because that's what it is, if you agreed to monogamy, this is cheating. I strongly suspect both of them agreed with different people to keep things monogamous, hence their panic.