YA fiction, set before and during WW2, book about girl whose father makes a machine so that she can relive her memories. Possibly published in early 2010s, Spoilers ahead.

[Micaela]

I believe the cover had a picture of two shadow silhouettes on a grey background or something along those lines. I think the book was set in the US but I'm not sure.

At the start of the book, the main character (who has black hair and purple eyes? And a love for tigers) gets expelled from her boarding school for sneaking out and so she goes to live on her dad's estate. Her dad is an elusive character and at some point during the book it's revealed that he's invented this machine that lets the user relive their memories or have good dreams forever or something.
I think the MC gets transported into this machine against her will, as a way to protect her during the war or to make her live forever. She sees happy memories/dreams of her dead mother though this machine and possibly spends years in that dreamscape, but I'm not sure about that part.
Her father's love interest is an actress I think? And at the end of the book she goes insane because she wants this machine for herself so she can 'be young forever' and she ends up burning down the estate with the main character inside, killing her.

Other plot points:
The MC is sexually assaulted either before the book takes place or off-screen in one of the first few chapters, and it's implied throughout the book. I think it's described as hands with white gloves reaching out touch her.

There's a male love interest who's actually a pretty central character. I think he lives or works on the estate or something. There's a scene where he catches the girl skinny-dipping in the lake near the house and she invites him to get in. At some point he serves in the military during WW2.

That's all I can remember right now, thanks for any help you can provide! Not being able to remember the title is seriously bugging me.

[Kris]

Micaela, what's the genre (which we need to add to the topic header) - e.g., teen (YA) or adult historical fantasy, thriller or horror?

[Micaela]

Oh sorry, I thought I mentioned the genre already. I think it would probably fall under YA

[Kris]

Thanks. I added "YA" to the header. Can you be more specific about genre or tone (e.g., fantasy, thriller, horror)?

[Kris]

Goodreads link for Froggy's suggestion - Stolen Girl by Marsha Forchuk Skrypuch

[Ayshe]

Or The Double Shadow?