Source ?

If no law has been broken, is dating another employee or cheating their wife a motive for firing someone?

The only person that should be able to fire him is their spouse and only of their mariage/relationship.

You as the CEO can't ethically and morally ask a subordinate employee to fuck you.

Why is that?

Nice way of outing yourself as an incel I guess

Imagine you’re a woman and your boss proposition you. Or gets flirty. Now imagine the pressure this comes with because it might put your big job and future work in jeopardy.

Why was it wrong of Weinstein to proposition possible actresses working?

It’s not hard to see that if you’re on a position of power over someone you must keep it professional.

There are already laws for abuse in place in many countries.

In the case of Weinstein, they identified as victims.

Brining the conversation back to context, no such case has been proven for Jensen.

dating someone != asking a subordinate to fuck you

In most juridictions there are laws against abuse of authority which applies if it is the case. How well they are enforced is a different matter but unless there is a victim I don't think there is a problem.

Consenting adults are allowed to be in relationships.

It is usually frowned upon in companies because of the complications that arise when people are dating.

For example it risks confidential information leaking or projects being delayed due to relationship dynamics.