There are as many reasons for divorce as there are divorces, ranging from finances to adultery, and none of them is the business of your child. Yet many children still in elementary school can recite line and verse of who did what to whom. How did they get this information? Eavesdropping is not to be minimized, but larger on the horizon looms the real answer. They were told the information by one or both of their parents. What?! Why on earth would you do that? The standard answer, by which we are always insulted, is that you expect us to believe that your child asked direct questions "to which I could not tell a lie." Really? That's pretty funny, because many of the allegations listed in the divorce papers you served upon each other are embellishments of the truth or downright lies. If you think not, reread your divorce papers and you'll know what we're talking about. Sure, your attorney put the allegations into legalese, but if you read and signed the documents, then the inferences and embellishments, which we'll call lies, belong to you.
Even if what you have to say is the truth, how could it possibly be helpful for a child to believe that his mother is an adulteress or his father gambled away the family money? What is the point in telling your offspring that things haven't been going well in the bedroom lately and sex got kind of "boring"? Do you really hate your spouse so much that you've lost control of your ability to censor what comes out of your own mouth? For the most part, your spouse is pretty much the same person they were when you married them, but maybe being irresponsible or blowing money doesn't seem so funny after ten or 20 years, or maybe one of you has grown up and the other hasn't, or you've grown in different directions. There are always reasons to harbor anger. If your spouse cheated on you, for example, you have a right to feel betrayed. What worse betrayal could there be to your self-esteem? But affairs and other indiscretions are merely symptoms of an eroded marital foundation, and that didn't happen overnight or without your knowledge.
If your children do ask questions, be honest without spewing out details. It is perfectly all right to say that you and your spouse don't agree on much anymore and neither of you wants the arguing. Or tell them that one or both of you simply hasn't been happy, but remind them that parents can divorce each other without divorcing the children. If you allow your anger and lack of impulse control to get the better of you and you say things you wish you hadn't, go back and repair the damage. If you muddy the waters, your children will have to swim in filth.
Your child needs two parents. You might not be a big fan of your spouse, but your children are, and you need to make sure it stays that way. If your goal is to protect your children because you believe your spouse to be an irresponsible oaf who won't keep his promise to pick them up after they've made plans for the day, let the day play out. You may be correct, and if so, you can deal with each situation after the fact, not before. Remember, just because your spouse never kept his promises to you doesn't mean he won't keep them to his children. Perhaps, however, it is your intention to make your spouse look bad in the eyes of your friends and family, and in a convoluted manner, you want to deflect attention from your bad traits by illuminating his.
Perhaps you feel a pang of jealousy that you seem to have taken on the brunt of the responsibility for the children, while he seems to be having all the fun with them. Worry not. It's the nature of children to choose fun and games over cleaning their rooms, but on some level they realize what's going on, and he won't end up with more points than you. Stability beats inconsistency every time. Making him look bad just makes you look bad, and no matter how much you might want to level the playing field, it's just not worth it.
We're all doing the best we can. Some of us are just better equipped to deal with life than others. Not blurting out every thought we have is a sign of adulthood. Some food for thought: One of the defining moments of adulthood is coming to the realization that even our own idealized or overly criticized parents were just doing the best they could -- or not, but stumbling through just the same, as we all are, falling down and finding the strength to get back up. This moment of recognition will come all by itself when the mind is ready to accept what it already innately knows. The next time your spouse stumbles, offer him a hand. He may do the same for you some day.