My advice to betrayed/left-behind spouses is to simply try to -- in every situation -- DO THE RIGHT THING, regardless of how your spouse is likely to react one way or another.
Ask yourself, "What is the right thing to do in this situation? What is the thing that God Himself would have me do, if He were standing right in front of me?" Don't "tick off" your spouse on purpose, and don't go around trying to be a d*ck, but if you are confident that you're doing the right thing, do not be concerned one whit if your cheating spouse gets upset or not.
Neither try to please them, nor worry about upsetting them. Just DO THE RIGHT THING.
