The bit I don’t get here is not that he didn’t say that he had to split at midnight, but the expectation that he wouldn’t.
I mean, if he’d said, “Yeah, let’s have dinner Saturday. And - just so we’re clear - I have no plans for later on,” we’d be looking at a thread about the outrageousness of his expectation of third-date sex.
Or if he’d said, at eleven, “Lovely evening, but I’m going to call it a night because I’m shattered,” we’d be looking at a ‘is he sending mixed messages’ thread.
Then again, if he’d said, “Yeah, I can do Saturday evening, but I have to leave at elevenish,” would the OP have said, “Ah, no - not Saturday then, because I was hoping to get laid. I mean, I’ve bought the waxing kit and everything.”
I think not. But if she would have, who’s being unreasonable to whom?
So what was he supposed to do?