Maybe it's the natural pessimist in me, but if an A does not die of its own natural death in the heart of the WAS, then they are likely to prolong keeping that A on a pedestal, make it into a martyrdom. I would think it best for the spouse to end the A of their own choice.
Under these circumstances, Sue should play it very, very carefully with her H. If her H tries to pursue the OW, perhaps he will push OW away even more -- eventually that will lead to H getting more and more frustrated (possibly taking it out on poor Sue.) Nevertheless, he will pine for what has been denied him. He will need a lot of time to figure out, if ever, that he wants/needs his M.
(((((Sue)))))
Best to tread lightly -- continue GAL'ing and DB'ing. If he decides to try to make his way back into your good graces, then you can begin to (gently) advise him that you've been on to him the whole time.
