Hoping this can be saved, but having doubts

[Olya]

I assume this takes us from WAS to WW territory, and that I should not be "friend" and hang out with her (we have shared activities) when there is on ongoing A.

If she has an ongoing affair, why does she need you? When I start a new relationship, I want to spend all my time with that person. Why isn't she spending that time with HIM? Can't HE go climbing with her?

You are not there to be a buffer that makes up for all the shortcomings of the OM.