Hi Afa
i agree no timelines - too much pressure for both of you
i know you - like the rest of us - will know when you are done.
i also agree no ultimatum - until you can handle being the one she doesn't choose.
However, from what W has said she knows OM is not what she wants longterm. Interesting friend has realised this in her sitch.

i don't have views on anger towards/forgiveness for OM - i've not been there.
i think i'd feel sorry for OM w his questionable morals and odd way of showing he cares for W by disrespecting her M
i think the forgiveness/compassion is for W and you have that in spades