Before Butter was born, I read a lot about preparing children for a sibling. I read about how to handle conflict between siblings, how to channel competition into cooperation, and how to find family tranquility.

I forgot to do that before our foreign exchange student arrived.

My boys helped prepare her room and drew her pictures to decorate her walls. They helped me shop for groceries she might like. And Peanut, our seven-year-old made a list of places we should take her. All very sweet.

But since she arrived, Butter is completely unimpressed.

Okay, that’s an understatement. He despises her.

When our temporary daughter talks to him, he shouts at her. “Don’t talk to me!”

I remind him that we talk nicely. That if you don’t want to answer, you can say, “I don’t want to talk.” But screaming at our friend “don’t talk to me, stupid Rosí!” is a one-way ticket to alone time.

She is flabbergasted by his rudeness. She has asked him to be nice, and she has told him she doesn’t like yelling. In fact, at one point she told him he couldn’t come in her room. She explained that, “Mommy talks nicely so she can come in my room. Daddy talks nicely so he can come in my room. Peanut talks nicely so he can come in my room. If you want to talk nicely, you can come in my room. But when you yell? You cannot come in my room. Goodbye.”

It didn’t work. He walked out of her room and slammed the door.

I’ve explained to him that he’s my son and I love him. That she’s a guest and we have to talk nicely. That I’m not her mom…I’m his mom.

But he knows that she’s the new baby in the family, taking time and attention from mom.

In her kind attempts to tidy the house, she moves his treasures and puts his shoes in the wrong place.

In her need to understand or clarify or get directions, she is taking from him what he believes is rightfully his.

And she came in full adult form, so he didn’t get his chance to poke and pinch her and test her pain tolerance as an infant.

She interrupts him when he talks, not hearing his thinking pauses in part because she’s unused to the rhythms of a three-year-old.

When he needs something, she often needs something, too. Sometimes she has to wait, and sometimes he has to wait.

She often calls me Mommy.

Worst of all, for him, she often doesn’t understand what he says. She gently tells him, “I don’t understand what you said,” hoping that he’ll repeat himself. Or miraculously become more articulate than his three years will allow.

He bellows, “I said ‘don’t talk to me,’ stupid Rosí!”

¡Ay, dios mío!

As our Dominican guest told me this week, my children are making me an old woman.