If he or perhaps she is "with their partner all the time" how would he or she be able to fly the coop & slip off to a knock shop in the first place tho?
In all seriousness & all jokes aside it is not uncommon to be infected with whatsoever all the while the host is blindly going about his or her business unknowingly infecting pretty much everyone he or she comes into contact with.
So the point I am making which got lost amongst Phoebe's feeble attempts at humour is that it would be virtually impossible to identify who infected who or when & how you were infected. A good example of this is the private escort I mentioned earlier in this thread who tested positive earlier today will be of very little help identifying the person's she has interacted with in the last 24 hours let alone the last 8 weeks. Furthermore the onus is on the infected person to identify those he or she has had contact with this is not a task for the health department or anyone else.
I really hope this has answered any questions anyone had because to be honest I have had enough of this discussion & I am going to return to posting funny memes & toilet paper jokes.