That's not being pessimistic. Pragmatic, but not pessimistic.
An affair couple will draw closer together if they feel they're under attack. They become a united front to battle the enemy, the enemy being those that would try to take their happiness away. The direct confrontational approach serves to reinforce the decision the WAS has already made.
Insofar as drawing comfort or hope because relatives or friends have categorized the affair as a "school-girl crush", their characterization of the affair is just as much a guess as anyone else's, and they have no more of an idea of how it will work out than anyone else does.
I do wish you the best. So far, from what I've gathered, your plan consists of 1. knowing things about the OM, 2. having some people tell you the affair is one sided, 3. praying that several things occur: A. that the relationship of mom, sis & OM can be healed (which are actually 3 things), B. that the OM ends the affair, C. that the OM talks to your W about going back to you, D. That your W is then convinced to come back to you.
