There is no simple answer to the question 'how much drink is too much', because it will differ for different people. However, the bright line is, is the woman able to give informed consent? All this means is that she says yes and actually wants to have sex with you. If she's capable of saying 'yes' and meaning it, and then does so, then it's not assault. Let's try to make this a bit easier. Situation 1: You meet a girl. She's completely sober. You persuade her to have sex, but it's not difficult, because she's up for it as well. Is it rape? Obviously not. Situation 2: You're in a hospital ward. There's a woman in a coma. You start sexually interfering with her. Is it rape? Obviously yes. These are extreme ends of the 'consent' spectrum. At some point of cognitive impairment, a woman goes from being able to give informed consent to sex to not being able to do so. Evans was convicted because the jury felt the woman in his case hadn't given informed consent and wasn't capable of doing so. Your responses are honestly a bit weird. Do you often find yourself in a situation where the woman the next day doesn't feel like she agreed to have sex with you? I mean, god knows I'm no lothario, but on the rare occasions I get my oats it's always been very obvious that we both just wanted to do it, whether we'd drunk anything or not. Here's a good maxim to live your life by: if you're not sure whether she wants to have sex with you, don't have sex with her.