Quoting jethro: I do feel a bit better, however, I kind of tried to tell myself that the emptiness will pass...and it pretty much has.
Your getting the hang of it... Most of the time the thing to do is to do ... NOTHING. Just ride it out for a while and most times it will pass. The time to concern yourself with it is when it shapes up into a continuing pattern, then its time to make a change.
Time has been flowing well for you lately and the momentum is still drawing you closer together, so there's no reason to stir the pot sorta speak.
In time, your R will develop to the point where OM will be only a footnote in her book and then it will not be an issue if he shows up in her presence. At that point you will need to let it go entirely, then any coincidental contact will have no effect at all on her.