This isn't likely what you assume from the headline.    

No member of the public was molested, raped, or similar.    
There was seemingly nothing non-consensual going on.   

This seems to be about an inter-departmental relationship, specifically an open relationship, involving a married couple and additional officers. The worst that seems to have happened is on-duty oral/sex and failure to report.    
I do like how when it is something like this they're all about firings, but when it is actual abuse of the public even with video evidence they won't fire a cop unless absolutely forced to.