I'm not sure. How do you get so drunk you can't even stand up by yourself (as happens in these cases), yet have the ability to force yourself on anyone? Anywhere you draw the line, there will be border cases.
The number of women who consent to sex, and then afterward decide they were raped, is very, very small.
Women don't typically call that rape, either.
Let's be clear:
1) The woman endangered her marriage by admitting she was in that room.
2) The woman subjected herself to some very negative responses by making the allegation.
3) We have only the guy's word of enthusiastic consent, a man raised in a culture where we are taught that good girls say no, and men are supposed to keep trying until they say yes.
What do you think the woman stood to gin by making her allegation, if she did not believe she had been raped?
If you believe the guy's story, he's not a rapist. An inability to remember consent is not a lack of consent.
I've had sex with my wife when she consented, yet was so drunk she could not remember it the next day. Not once has she said that she didn't want to have sex the previous night.