Would it though? I'm not a lawyer but what's the difference between the employer understanding there is a consensual relationship and then sexual harassment is

Would it though? I'm not a lawyer but what's the difference between the employer understanding there is a consensual relationship and then sexual harassment is accused versus not knowing about a relationship and the same thing occurring? It's not like the company knew about sexual harassment and once they know about it they'll likely be terminating the offending party. So why would them knowing there is a consensual relationship add to their accountability?