Your W is having an affair with Roy. Accept it process it and never mention it again. Every time you do it builds you up as the adversary and bonds them together.
Be thankful that she’s having an A with a loser because once she stops running on emotions she will eventually see him for who he is as a person. There is a thread on here for a former poster “Hoosjim” if you can find it sounds similar. He eventually reconned with his W after she had an affair with a toe truck driver.
No more relationship talks and try to make yourself as scarce as possible. Your ride is just beginning and will take many months/years before it plays out.
SteveLW a vet here has stated that 90% of WWs will eventually want to reconcile. My friends parents reconciled after 35 years apart.