@Soluiz not to apply real contemporary laws and morals on a fantasy story about aristocracy but I'm pretty sure the Jury would not look at a case where the woman was blackout drunk and out of character (the whole juggling and cocktail bit) and a man who was at best tipsy and say its her fault for coming onto him. Morally, she was obviously too drunk to consent from what we know. By law (depending on country) it heavily hinges on whether the jury believe the ml could have reasonably believed she was sober enough to consent (evidence points to otherwise).
We don't know the details of the night, but ml seems fully cognisant of what happened and while he keeps pulling the "you took my first night card" I based on how he's been characterised so far, I find it hard to believe he was forced into anything. Her going up to him and saying "hey lets do it, it'll be worth your time" or coming on to him doesn't mean he would have been in his right to follow through if she was too out of it.
You're right to say someone being drunk doesn't absolve them from anything they do as a result (even if they don't remember) but so far unless we learn she pressured him emotionally or physically theres not much making him out to being the victim.
Regardless, it doesn't seem to be a bit deal in this story since the person who blacked out doesn't seem perturbed by the actual act itself.