Like parents since the cave men and women, mine didn’t always agree. But, they didn’t need a library of self-help books to parent as a team. When an authoritative decision was needed, they would disappear into our knotty-pine paneled den and close the door, leaving my brother and me to wait – on pins and needles. When their muffled squabbling ended, they would emerge together and present a united front as they announced the verdict.

Most times, we could have guessed the outcome. My parents’ guiding principles were rooted in common sense and old-fashioned family values. And, if nothing else, their decisions were predictably (and annoyingly) consistent. “No,” they’d announce, “you may not invite your boyfriend to the beach for our family vacation.” “Yes, you’ll be attending your second-cousin’s wedding, even if it means missing the homecoming dance.” “No, you may not have a car for your sixteenth birthday. We don’t care whether Mary Stuart Gillespie or Johnny Williams got one.” My brother and I didn’t dare question our parents’ process or the end result – not in front of them, for sure. In our house, their word was law.

I figured all marriages worked that way. So when my first marriage didn’t, I felt a twinge of alarm. Was it a basic difference in parenting philosophies or was it the behavioral problems we were facing with our son that produced the tension? After all, even healthy marriages can be torn apart when learning issues or addiction enters the picture. Like the black light a crime scene investigator waves over the hotel bedspread to expose forensic evidence, a child’s substance abuse, for example, exposes the ugly parts of a marriage.

When families are blended by remarriage, the problem that was once yours or mine, becomes ours. The substance-abusing child is a pre-existing condition, like high blood pressure, adding a layer of stress to an already challenging family dynamic. The ups and downs of addiction are rarely convenient, so it’s not uncommon for a stepparent to have a tough time empathizing.

I wrote a blog post titled The Wedge, March 5, 2013.  The wedge exists in every marriage where a child is in trouble.  It’s not an event with a beginning and end. It just is. The real test comes when you’re faced with tough decisions and how you, as an married couple, or divorced parents, decide to deal with it.

The best advice I ever got is this: whether your marriage is made of stone or has crumbled beyond recognition, focus on carving out a single channel of communication where the child is the priority and everything else between you – the grudges, tensions, petty squabbles, skin-crawling irritations – are off limits.

Work as a team.  You’re in triage mode.