Now, 2 questions.
Part One. Given that these two people were drunk together and alone together, the guy being so drunk himself he claims not to remember all of the evening, is it unreasonable that they slept together? He could be lying or he may genuinely not remember.
Part Two. New information: he has lied about going to see her whilst she (and possible he) was drunk. Is it believable that they didn't sleep together, then or any other time?
I'm really grateful to everyone who responded to my post about trust. Thank you ♥