Keep your conflict to yourself
You're angry, scared, and your sadness hangs off you like wet sandbags. You feel your husband's infidelity was an abandonment of you and your children. You want them to know what he's done. They should know the truth, you tell yourself. But your need for a catharsis will not help you or your children. All they will hear is that their father is a bad person - and they will assume that they did something wrong to make him want to abandon them (a suggestion you will have planted in their heads and one they will nurture for years). You will be shoving a wedge between the children and their father - one that they will recognize when they get older, and which may spawn significant resentment toward you. How do I know this? It's axiomatic - and it's my experience after 18 years of family law practice and 13 years of representing the interests of children, but don't take my word for it - consult with a child specialist, a cooperative parenting expert, or a family therapist. And no, my example notwithstanding, betrayal is gender neutral. It knows just as many wives as it does husbands (but thankfully, many parents out there are committed to each other - they're just not the subject of this paper).
Attend to your emotional and psychological needs
Your feelings of rejection, your uneasiness, your grief - they're all a normal part of the divorce process, but if you do not address them, they can persist long after the marriage is dissolved. When you get into a funk, it's easier to stay in fetal position and to pull a blanket over your head than it is to get out of bed, but do it. Get up. Call that friend who always manages to push you back into reality. Do whatever it takes to step out of the fog that you've been wearing like a heatsheet. Instead of spending your lunch hour ruminating, give yourself permission to cease the self-flagellation. Try on vintage dresses at a consignment shop or hunt for some fabulous flea market finds that you can repurpose. And instead of venting to your colleagues (not a great idea), consider speaking to a therapist, ideally someone with some expertise in dealing with families in transition.
Be respectful of your child's other parent
It's not enough to abstain from demeaning your spouse in your child's presence. You have to make a concerted effort to speak well (or not at all) of your child's other parent to third parties, unless you want your child to suffer the consequences when those third parties repeat what you've said to their children and their children repeat it to your child. Your child sees himself or herself as an extension of you and your spouse, so when you badmouth the child's other parent, your child is likely to internalize your insults.
Share the news with your children together
You are, G-d willing, going to be parents of the same children for a long time. You will be at doctor visits, parent-teacher conferences, birthday parties, soccer games, tennis tournaments, swim meets, ballet recitals, drama productions, and graduations together...and eventually weddings, baby showers, baptisms, confirmations, barmitzvot.... If you want to minimize your children's discomfort, present a united front, starting with telling them about the divorce together. If one parent tries to beat the other to the proverbial punch, the children might perceive the divorce as being one sided. They may even perceive (however wrongly) that the other parent doesn't care about them. Forget your need to claim superiority in the marital commitment category. Make your children's psychological wellbeing your priority. Let them know that you and their other parent will continue to parent as a team.
Consider the consequences - make empathetic decisions
When making decisions that impact your children, start by imagining what it would be like to be on the receiving end of whatever decision you are making. How would you feel if your mother uprooted you from the only home you'd known and moved you into her boyfriend's apartment before your parents' divorce was final? How would you feel if your father's girlfriend started picking you up from school and spending his parenting time with you? When your children grow up and speak to their respective therapists about their childhood, what will they say about how you safeguarded them in divorce? Will they be thankful that you road the moral high ground, or will they bemoan the myriad of ways in which you and their father used them as pawns in your conflict? Will they blame you for their endless string of failed relationships and inability to trust?
Invest in your family, not in litigation
A judge doesn't know you and your family (and if he or she does, then he or she should probably be recusing himself or herself from hearing your divorce case). So, unless you want a stranger deciding what kind of custody and parenting time arrangement is best suited for you and your children, talk to your attorney about potential avenues for reaching an amicable resolution: negotiation, mediation, a collaborative process, judicially hosted settlement conference, etc. You might also speak jointly to a child specialist who can help you understand what kind of parenting time schedule would be best for your child depending on his or her age and stage of development, your family dynamic, proximity of you and your spouse to each other, and any other relevant factors - including your desire that each of your children be able to maintain a quality relationship with each parent. Ask about equal parenting, co-parenting, parallel parenting - the names are less important than they kind of parenting arrangement they represent, and what may be best for your family may not be best for another. So, instead of engaging in legal warfare in the hope of ending up with the same custodial arrangement as your neighbor, colleague, or best friend's cousin's nephew, do your research and find out what kind of arrangement is best for your family - for your children.
Always let them know their loved
Children crave security, stability, consistency. Divorce upsets the balance with which they are familiar, even if that "balance" has been less than steady. They will be apprehensive about how the divorce will disrupt that to which they've become accustomed. They will want to know where they will live, whether they will attend the same school, how often they will see each parent, whether they will live with their siblings, and whether the dog they love will share their home. You may not have all the answers yet, but what's most important is that when you answer them, you do so in a patient, loving, and truthful way. You and your spouse should have at least an agreed upon temporary parenting plan before you break the news of the divorce to the children.