SOLVED. YA fiction. Recently made rich girl is never satisfied with what she has and is forever jealous of everyone around her. [s]

[Claudia]

SPOILERS


Looking for a book I read back in the early to mid 2010s. It alternated perspectives between two sister who had recently become rich when their mom remarried. The parts I remember mostly followed the younger sister, who is notoriously jealous of other people, namely her older sister's boyfriend (possibly named Kevin?) who she has a secret crush on. Or at least, it's a secret in her perspective, but both her older sister and the boyfriend know. But neither of them take it seriously, and consider it a cute, puppy love kind of crush.
There's a whole thing where the younger sister either wants to throw or attend a party, so she goes over to the popular, bitchy girl's house at her pool to find two girls she doesn't even like to either invite them or invite herself. There's a detailed description of how they're very alike in personality, but complete opposites in appearance. It talks about how one is already beautifully tanned, but is still trying to get tanner, and how the other one is "sunbathing" under an umbrella, so she can stay extremely pale. The younger sister later finds her mom's old wedding dress (from her first wedding, I think?) at a thrift store, and plans to rip it and style it up for the party, which the older sister said was tacky, but the younger one does anyway.
Meanwhile, the older sister is crushing on, and later hooks up with some guy (possibly a coworker) with tattoo sleeves (in a sleeping bag?? in the bed of his truck??) even though she's still technically with her boyfriend, even though she's been pretty much over the relationship by this point. She does dump the boyfriend, and then he immediately turns around and hooks up with the younger sister, and then ditches her after the deed is done. When the older sister finds out, she's not even mad or jealous, but sad for her sister, and at how her ex used her crush on him to his advantage.
I think the book ends with a flashback of the two girls (pre rich stepdad) sharing the older sister's bed during a stormy night because the younger sister is too scared to sleep alone. But she doesn't go to her parents because they promised to buy her a charm bracelet that other girls at school have, if she can just stay in her own bed for a whole month. And one of the sisters (can't remember which one) reflects on how the younger sister is never satisfied and always wants what others have.

[Becca]

All You Never Wanted by Adele Griffin

[Claudia]

Becca wrote: "All You Never Wanted by Adele Griffin"

yes! that's it! thank you!