The affair isn't the issue, or at least not the only issue, it's who he had the affair with.

At the end of the day Jensen chose to have an affair with a senior officer of a company strongly suspected of bypassing trade restrictions and should have known that it would be a terrible look for Nvidia and himself. Even if he didn't suspect her of being an agent of China, even if he didn't believe the allegations against Mega speed, even if he had no intentions of passing confidential information or aiding in bypassing trade restrictions. He knew it would carry the appearance of all those things.

That is the unforgivable lapse in judgement.

"you can be totally trustworthy in the realm of business, yet not in romance."

If you can't adhere to the terms of a voluntarily-entered personal contract with a person to whom you've promised utter faithfulness, why should I believe you'll be trustworthy with regard to some boring, impersonal business contracts?

yes, that exactly the point. i want my colleagues to behave correctly on the job - i don't care if they have 3 boyfriends or cheat on their partner. it's not the point. it can be fun to gossip around the coffee machine, but that's about it. nobody should be fired for having an affair.