Dear Amy: My sister “Kelly,” who lives out of state, won’t be joining us for Christmas because Mom said no when Kelly asked if she could bring her married boyfriend home to meet the family.

I am firmly in Mom’s corner and am hurt and disappointed that she is choosing him over family. Kelly is my best friend.

Kelly says the situation is “complicated,” but for me it’s not actually that complicated.

My morals can be flexible at times, but marriage is an absolute line in the sand. I’ve been married 28 years and to me, marriage is SACRED.

Am I being too judgy? Do I have to be supportive?

Kelly is bound to bring him home at some point. I have no idea how to act.

She is so much more than a side piece, and I’ve told her this many times.

In the meantime, I’m simply asking for someone to pour a little more liquor into my eggnog.

– Sister

Dear Sister: I wonder if there is ever a time when an extramarital relationship isn’t complicated. Of course it’s complicated!

Bringing your married squeeze home for the holidays isn’t exactly the makings of a Hallmark Channel movie, although maybe it should be. (“Stay tuned for ‘Christmas Complications.’ Watch the snowballs fly when a lonely spinster brings her married boyfriend home to their Christmas tree farm – featuring the holiday hit: ‘Baby, it’s Scold Outside.’”)

You are being judgy, but feeling (or fearing) harsh judgment is the eternal sisters’ lament. In many families, scrutinizing and judging one another seems to be baked into the sister relationship.

I think you should consider making a deliberate choice not to judge your sister.

You have your point of view; she no doubt anticipates it. (After all, you’ve already called her a “side piece.”)

And who knows – maybe she lacks self-awareness, self-esteem, or discernment because you’ve been waiting in the wings, ready to weigh in.

Perhaps you could deliver this sentiment as a holiday gift: “I’m not here to judge you. But Mom’s not ready and I’m not ready to meet this man. We’ll miss you this year, but let’s make sure to talk on Christmas Day.”

Yes, you should be supportive of your sister as a person, but you are not required to support all of her choices.

You can email Amy Dickinson at [email protected] or send a letter to Ask Amy, P.O. Box 194, Freeville, NY 13068.