SOLVED. Historical romance set in England. Heroine wants to be ruined by a man but enters the hero's bedroom by mistake. [s]

[Joyce]

I read this book this year or perhaps last year and there's a possibility that I found it here, actually. It's a historical romance, maybe just a novella. The story happened during a house party and I think it's being held on the h's house. The h is a young woman who likes a certain young man and since he attended the house party, she planned to enter his room at night. I'm not sure if she really wanted to have sex with him though. Anyway she ended up entering the wrong room- the room where the H was sleeping. The H, if I remember correctly, is titled and a rake. He's also older and may even be a friend of the h's older brother (I may be mixing things up). The H mistook the h for his mistress and, of course, had sex with her when she entered the room. The next day the H noticed that there's blood on the bed sheet and thought that perhaps his mistress (a widow, I think?) was on her period, but then he found out that his mistress wasn't in the house and he set out to find out who's the woman he made love to.
I don't remember much after that but there's a scene where they're all eating outside and the h sat beside the man she likes. Something happened and the man said something bad to the h and the H swooped in or something like that. There's also this detail, but i think it's some sort of a spoiler. (view spoiler)[ The H warned the h about the man because he's not actually a nice man like the h thought he was, I think he's in debt? (hide spoiler)]

Thank you in advance!

[Emely]

It sounds like If the Duke Demands by Anna Harrington.

A LESSON IN SEDUCTION . . .

Miranda Hodgkins has only ever wanted one thing: to marry Robert Carlisle. And she simply can't wait a moment longer. During the Carlisle family masquerade ball, Miranda boldly sneaks into his bedchamber with seduction on her mind. Soon she's swept into rock-hard arms for the most breathtaking kiss of her life. But when the masks come off, she's horrified to find herself face-to-face with Sebastian, the Duke of Trent-Robert's formidable older brother.

Shocked to find Miranda in his bed, Sebastian quickly offers her a deal to avoid scandal: He'll help her win his brother's heart if she'll find him the perfect wife. But what begins as a simple negotiation soon spirals out of control. For the longer this reformed rake tries to make a match for Miranda, the more he wants to keep her all to himself.

[Kris]

If the Duke Demands by Anna Harrington - Emely's suggestion

[Joyce]

Thanks but I don't think it's that. I'm pretty sure the H and the other man are not related. I'm just gonna add that to my TBR list!

[Ayshe]

A Duchess in the Dark by Kate McKinley?

[Joyce]

Ayshe wrote: "A Duchess in the Dark by Kate McKinley?"
Yes!!! That's it! THANK YOU SOOO MUCH!!!