OK... a little reading between the lines here but let me give this a try...
Sounds like the mated pair are still in a quarantine tank. Correct? If so, then the very fact that something new has been introduced to the quarantine means the clock gets reset back to zero before they can be moved into the main tank. In other words, if the mated pair were in there 2 weeks out of a 4 week quarantine time... then you just set yourself back 2 weeks because you now have to wait 4 weeks again to make sure no illness has been introduced. Basic rule for quarantine is that you have no change in inhabitants for the entire time of your quarantine period.
The other issue may be that introducing a "third wheel" to a mated pair could really throw the existing relationship out of whack. Especially if the pair truly weren't mated to start with.
Personally... I probably would've had a fit over it too! But I can kind of see you were in a bind... what do you do when your buddy brings over a clownfish? "Friends" bearing gifts for your tank can be a really really bad thing sometimes.