A drunk knows that something he is about to do is wrong, but he wants to do it (usually for pleasure) and he just doesn't give a damn.
Drinking merely curtails ones inhibitions. I don't believe that alcohol is ever going to make someone do something that he doesn't want to do on some level when sober but was just afraid to do it.
if a man is really so incredibly drunk that he truly has no idea what he is doing, then he will probably lose his legs and kiss the ground and he will pass out. He wouldn't get an erection, pull his pants down and have intercourse with a woman.
Totally agree. ( adapt from http://www.myfatpocket.com/sex-love/cheating-when-drunk-forgive-forget-it.html )
Ps:// For a friend :) , I do hope you consider continuing your relationship with him.