There are people who believe two intoxicated partners having sex is mutual rape or nonconsent. There is also a lot of education on college campuses these days promoting the same idea. I'm not arguing for or against your point, I just want to point out that there are people who adhere strongly to different opinions. I'm sure these situations can be triggering for some people.
Me personally - I love pushing boundaries, provided there is an intelligent exploration of consequences. Consequences are interesting, the meat of the story. I would only find a boundary-pushing situation offensive (more disinteresting than offensive) if the consequences were ignored, minimized, or overlooked, because it destroys the credibility of the situation. I believe the exploration of consequences is a powerful thing.
That being said... the situation in question doesn't sound like any variation of the extremes, just standard fare romance mirroring everyday life.
To the OP - there is always someone who will be offended by something. Everybody's buttons are pushed differently, and ultimately, I think staying true to your genre, and having the book marketed accurately for its content is the best you can do. When someone has an opinion vastly different than your own (one of the reasons I love posting here
), it's always good to take a step back and self-reflect, examine the scene from another point of view. It doesn't mean anyone is right or wrong.
There are ways to signal responsibility in a situation that involves alcohol, like calling a cab, but I don't personally believe the purpose of EVERY scene containing something potentially offensive to someone is to preach morals or responsibility. If your purpose is to stimulate the reader to ask deep questions about morality, IMHO, there are FAR more interesting ways to achieve this than a few simple lines of preaching. Sure, it also serves many characters and situations to do things that are considerate, respectful, or self-preserving, and the story could likewise feel weak if courtesy was ignored.
I feel like this is an issue similar to the use of birth control before sex. Some authors believe they should always write that one line where someone whips out a condom. I personally think it's something that needs to be evaluated on a case-by-case basis. Some readers will care, some won't. There are so many variables to what an author can be trying to achieve that it's impossible to make blanket statements about "what people should do." Sometimes I prefer ambiguity to let my imagination fill in the blanks - I'm allergic to latex, so I'd rather assume heroine took her birth control in the morning, and I don't need to dwell on it.
You can look up any bodice ripper with great reviews on Amazon and see the same thing with complaints. If you scroll through the reviews for long enough, there will always be the occasional one-star rating for rape. Are the reviews fair? If the book is marketed like a sweet romance, yeah. If the book has a trigger warning for dubcon inside and is marketed as dark romance? That's not enough to stop some people from complaining. And trigger warnings themselves are a dicey rabbit hole...
The person who complained is not your target audience. It's impossible to please everyone. Does what you're writing align most clearly with the storytelling goals you're trying to achieve? If yes, move on.