Cut sister slack, not out of your life

Q. My sister is 25 and six years my younger. She is someone I love dearly and is my best friend despite what seems like a significant generational gap. She just moved out of my parents' house, loves to party, and finally secured a stable job thanks to family connections - meanwhile, my husband and I recently bought a home, adopted a dog, are expecting our first child, and are established in our careers.

Last summer she started dating a guy my age, her very first boyfriend. She let no one meet him while also not painting the prettiest picture - of his frustrations with her for being late, his drunken emotional rants, etc. When I finally met him, a month into their dating and right after he told her he loved her, I found him to be nice enough but had very strong reservations. Soon after, multiple mutual acquaintances shared warnings, while also letting me know he had been making my sister the butt of jokes to his friends.

I made a difficult decision to tell my sister everything I had heard. I truly believed she needed to know.

Her reaction was shocking. Before hanging up on me, she stated with expletives to stay out of her life. She also immediately engaged my parents, claiming to be victim to my attempts to sabotage her relationship. Her boyfriend denied everything.

Parents are now furious with me. Sister and I have attempted to talk, but she gave an ultimatum: Like him or else. My response: I don't like him but will be perfectly nice to him (as I have been). She still cannot accept my opinion and continues to wage war using my parents. Did I mention I'm pregnant?

Husband thinks I need to set an example and keep making efforts at peace. But I'm just hurt, angry, and so extremely disappointed in who she is showing herself to be that I just want to move on with our lives sans Sister. Especially with a little one on the way - I don't want our daughter exposed to this kind of behavior.

Parents have since apologized for their reaction but that relationship is strained.

Is it reasonable for me to amputate this bad limb and move on?

A. Amputate? Bad limb? Wow.

Sure, if your plan when your daughter hits a young-adult rough patch (practically redundant) is to cut her loose after she doesn't follow your maternal advice to your liking.

Yes, you did mention you are pregnant.

And emotionally settled, and responsibly housed, and professionally stabilized, and sororally bonded despite your mother-figure/wild-child dynamic.

So I can conclude stagy throat-clearing you have the mature perspective to recognize how your idea of protective concern - in trying to save your sister, then in trying to save your unborn child from said sister - could come across to her as the last straw of smugness. Right?

Siblings don't have the luxury of taking incidents between them out of lifelong context - not if they hope to be fair. Independently, your sister's reaction is shocking and offensive, but as the fruit of a deep-rooted impulse to obliterate the hapless-little-sister trope, it verges on sympathetic.

This is not to defend her profane eruption or ongoing war. Both are not only uncalled for, but also proof of her immaturity that she can't have intended to hand you.

However, if you regard this one episode as the last word on who your sister is and will ever be, then you're being as shortsighted about her as you think she's being about love.

Recall when she was a child to your adolescent. Presumably you made her the butt of your hormonal horror show on a renewable basis, and presumably she didn't renounce you for it. Presumably she hung in until you shed that skin and a kinder big sister emerged.

So I'm with your husband on this one, with a twist: Set an example not for your sister - because any further maternal impulse toward her will be highly inflammatory - but instead for yourself as a parent-to-be. Recognize that you're not going to be thrilled with every incarnation of someone on the path to full maturity, and learn how to keep yourself at a loving remove as metamorphosis does its work.

And, learn to admit when you've overstepped and apologize for it - even when your intentions were good, when your concerns were founded and when apologies owed to you apparently aren't forthcoming. "I thought you needed to know these things, but I didn't understand till now that what you needed from me more was to recognize that you can take care of yourself. I am sorry for that."

If after that you still want some distance, or your sister insists on it, then you're both entitled to it. Just have the grace to treat it as room for you both to evolve, please, versus the - again, wow - "amputation" of something too diseased to save.

• Email Carolyn at tellme@washpost.com, or chat with her online at 11 a.m. each Friday at www.washingtonpost.com.