Dear Carolyn: I have a close group of girlfriends I have known for decades. We have helped each other through very difficult times over the years, and laughed and celebrated a lot, as well. As you can imagine, we have also gotten to know each other's husbands and children very well.

I recently learned one of our girlfriends has been having an affair with one of the husbands. It has been devastating news, on many levels.

The core question for me, beyond of course surrounding and supporting the friend who is the wife, is how I move forward with the friend who is having the affair.

Is there a scenario where time (or something other than time?) might heal something like this? I am mourning the loss of the friendship, but angry at the hurt this has caused.

Carolyn says: The answer is that there is no answer. There is no "how" — at least, not one I can supply for you. You move forward only how you want to and are willing to.

You can walk away from the unfaithful friend. That sounds justified, and avoids moral line-drawing.

You can also stand by her, frailties and all. All decisions have consequences and this choice would likely have steep ones — costing you this whole group, perhaps — but it's still your prerogative.

Or you can take a break from the cheating friend to see how you feel over time. You can prop yourself open to forgiving her under the right conditions, like her taking full accountability; maybe your conditions will eventually be met, maybe they won't, maybe you'll stop caring.

Every friendship involves looking the other way on temporarily horrible personhood, after all, and it's not for me to dictate the limit of anyone's neck.

Firmly planted

Dear Carolyn: My husband's best friend and his wife, after a variety of diets, have permanently settled on a plant-based diet. It has become a philosophy they love to study, promote and preach about. Now, nearly every meal with them includes conversation about the benefits of plant-based eating, and it pops up in conversation even while the guys golf or do other activities.

We have become frustrated. Even after telling them we are happy they've found a diet that works for them and do not wish to keep hearing about it — still it continues.

Carolyn says: If the core affection endures and the preaching exists independently as its own nuisance, I offer a few less-drastic options.

Such as: "We know the costs of our diet and choose it anyway. What will it take for the preaching to stop?" Square up for the come-to-Beano conversation. Maybe if they feel heard vs. merely deflected, they'll back off.

Or you can deploy humor: "Every time you talk diet, I'm ordering steak." Or lighthearted accommodation: "OK, we'll take two minutes of plant infomercial — go."

E-mail Carolyn Hax at tellme@washpost.com.