They first have to sober up. Then check.
You check by listening. If he pretends, he will catch himself out, if you are listening carefully. The trick is, if he pretends, not to let him know that you have noticed. Then he will truly reveal himself. Body language can also be pretty revealing too. A friend of mine who has a professional training in a special field said that it is rare that someone can keep up an act after 18 months.
Idoagree - when to be patient and when to cut it loose? Listen to your heart. My own way of doing it is to make sure that before I go on a date, I am truly centered (i.e. relaxed and not going to be thrown easily) and if the worst comes to the worst, either you have a good evening or a rotten one. Never put yourself in the position where you have an unsafe one. If someone makes you feel uneasy with the "crap", you are always free to leave. I did this once with a guy who was devastatingly handsome. We went to a restaurant and he was rude to the waitress. End of story. I called a taxi and was gone.
Yep! I doagree. When something tells you that something isn't right, that's because it's W R O N G.
Somewhere inside you you have heard it, in spite of his handsomeness, great wallet, gentlemanly behaviour.
LISTEN TO IT.
I'm sorry you had to live through that and hope that next time, you enjoy the evening and if you don't, keep asking yourself WHY! (Not what he wants, but what you are worrying about!!!) It's your relationship too, it's your heart too.
You can't, aside from looking at basic behavior, which is pretty obvious. If he gets wasted every night, obviously that's a bad sign.
Beyond that, people can say anything about what they want in a relationship and you can't really check it.
Gee...I can here your bio-clock ticking all the way over here!