Q: My friend and I read your column and we have recently had a disagreement. She feels because you have been divorced, you have no right to give readers advice about maintaining a relationship. I feel because you have been divorced, you may give even better advice than someone who has never been through a breakup. So, for the record, is there any time you would say leaving someone is warranted?

A: Sounds to me like your friend isn't taking into consideration why someone might divorce and regards all divorce as frivolous. Truth is, there are definitely reasons that make a breakup understandable and in the best interest of any children to be considered.

Before we get started, let me first say that this column is about ex-etiquette or "good behavior after divorce or separation."

I started writing it 20 years ago in an effort to help those dealing with the trials of divorce and remarriage. It seemed that joint custody had changed all the rules and people were having trouble navigating the waters. I saw mediation work firsthand and became a child custody mediator as a result.

Until then I thought you break up, you make each other's life miserable. That was the nature of the beast.

I developed the 10 rules of good ex-etiquette to help prevent that misery.

That said, divorce should not be a frivolous decision, especially if there are children involved. It all boils down to your safety, your partner's safety and the safety of your children — and I will support anyone who chooses to leave if they face at least one of the following:

Domestic violence or abuse of any sort — leaving may be a matter of life and death. It is a parent's responsibility to keep the children safe and if the other parent is hurting them or the children, leaving the relationship is certainly understandable.

Second, if your partner is abusing drugs and/or alcohol on a regular basis and is not in recovery. When under the influence, decisions may be questionable and it has been my experience that's when violence often comes into play. Lying is commonplace. Once again, in cases like this, leaving may be more about survival than keeping the relationship together.

Third, divorce may be warranted if your partner has been diagnosed with a mental illness and is not following their doctor's orders, and/or is not med-compliant. Notice the qualification here: Not all mental health diagnosis requires medication and there are those with such a diagnosis who are fabulous partners and parents. However, when spouses stop taking medication prescribed to help prevent psychosis or behaviors that may harm family members, and become irrational or unpredictable and dangerous, again, separation is understandable.

Finally, if a partner is unfaithful, divorce is certainly warranted. Some couples can overcome it. Some have told me their marriage is actually better now that they have faced it. That has not been my experience, but I will certainly support someone who chooses to stay — and understand why someone chooses to leave.

Tell your friend to write me if she disagrees.