The grief you can understand. When a spouse breaks the marriage, when a grownup child repudiates the gospel, it comes as a shock, as a loss, and where there was love, there will be mourning.
But there's another thought that is often expressed:
"We married in the temple. How could this happen?"
"We had family prayer and home evening and we took the kids to seminary and all their church meetings and they all served missions and went to BYU. How could this happen?"
While such feelings are natural, there is no logic behind them. Or, rather, the logic is of a kind that doesn't fit within the gospel of Jesus Christ.
What we're really seeing here is magical thinking. "If I say these words, perform these rituals, make these incantations, assemble these ingredients, I will end up with a charm that wards off bad happenings."
This kind of thinking exists in all societies at every level: If I do this, I can prevent that.
If I put all my plastic bottles in recycling, I can placate the demon of global warming. If I give up candy, I'll lose weight. If I obey all traffic laws, I won't have any accidents.
It's so easy to forget how causality actually works. Even if you obey all traffic laws, that only means you are less likely to cause an accident. There still might be rain-slick roads, or an oncoming drunk driver. All your obedience won't necessarily prevent such an accident.
By all means, give up candy. But if your heredity wants you to have a pear-shaped body, potato chips will do the job as well as candy ever would.
Even if global warming were caused by human carbon emissions, there is no present course of action that can significantly reduce atmospheric carbon in the next century.
Magical thinking is the idea that by sacrificing something, performing some magical action, you can prevent causally unrelated misfortunes.
It's perfectly understandable that LDS Church members might be misled into thinking that way. For instance, we've all heard the stories of tithe-payers whose sacrifice was rewarded with financial sufficiency.
And don't we have Doctrine and Covenants 130:20-21? "There is a law, irrevocably decreed in heaven before the foundations of this world, upon which all blessings are predicated — and when we obtain any blessing from God, it is by obedience to that law upon which it is predicated."
What we can easily miss is how causally specific this promise is. The blessing is predicated upon obedience, not just to any law, or even to all laws, but to the particular law "upon which it is predicated."
So when we marry in the temple, what have we done? Performed a magical ritual that guarantees that our marriage will endure? Not at all.
When both partners in a marriage are worthy to enter the temple and make those covenants, the chances of a successful marriage are vastly improved — but not magically guaranteed.
The blessing you definitely receive is the ceremony in the temple. But that only marks a beginning. The two of you still have to keep making the choices that will make your marriage thrive.
Likewise, we're supposed to teach our children to pray, and to walk uprightly before the Lord (Doctrine and Covenants 68:28). My parents taught me to pray. From the beginning of my life, I was taught to say these words: "Help me to grow up and go on a mission and get married in the temple."
Those words beside my childhood bed taught me what was expected of me, but I still had to earn faith by my own effort and experience as I got older. The mission was still my choice; so was the temple marriage.
The reward my parents received from teaching me to pray and walk uprightly was a child who knew how to pray and what "walking uprightly" consisted of. I clearly understood what the choices were.
But nothing my parents did deprived me of one iota of my agency.
Nor does a temple marriage remove from either partner any of their freedom of choice. Pride, selfishness, weakness, sin, rebellion, all remain possible, because agency is never rescinded.
No Latter-day Saint, however faithful, can perform any magical act that removes or reduces any other person's agency. Period. Ever. That was made clear in the council in heaven before we were born.
It can be a terrible surprise and a source of agonizing grief when a spouse or a child (or a parent, or anyone!) shatters our hopes, violates our expectations, breaks their own promises, denies their previous testimony.
But the Lord has not cheated you. He never promised to enslave anyone else to your wishes.
Nor did the Lord promise that he would suspend the laws of nature to your benefit. That rain-slicked highway can still take away control of your car, no matter how carefully you keep the traffic laws. The earthquake can still bring the house down upon you; the tornado can still sweep it away.
What the Lord has promised is that your obedience will mean that you will cause no evil, and that when bad things happen to you, you will be comforted and sustained.
It isn't magic. It's natural causality, it's the law, it's the promise of God to every child born into this world. The blessings that can be obtained are obtained by obedience.
There are things we wish for which can't be obtained by our actions alone, because no one's agency is taken away, and nature takes its course, and God plays no favorites (Matthew 5:45).
Magical thinking is from the other plan, the one we all rejected.
Our Father will keep all his promises — but only the ones he actually made.