Unreasonably high expectations can lead to disappointment, resentment, and anger--which do not bode well for a successful marriage. Best to strive for transparency, air matters out early and deal with hidden motivations, especially more nefarious ones.
What you thought would never happen to you officially has. After a 30-year marriage: divorce. Regardless of how everything plays out when the dust settles, there's a good chance that the dynamics of your family will have a new look.
My dad came out 14 years ago when I was 21. Since then, my parents have divorced. My mom remarried a few years later while my dad made up for lost time in his gay dating career. Life in our family has been.. interesting.
If you are an adult child of divorce, it's no longer up to others to help you bounce back from your parents' divorce. But in order to heal and adjust, you must move out of the place of being a victim and take responsibility for your recovery.