I have a complicated question concerning the verse on marriage to 4 wives. Is this realistic considering that it is very hard to treat 4 humans beings equally?

More importantly, how can we differentiate between a man cheating on his first wife, versus a man trying to get a know another women to make her his second wife. Where is the line crossed? When is it considered cheating on your first wife and when is it considered just trying to get to know a woman to make her your second wife?

For instance, imagine that I am a single woman who is talking to a married man. We have gone out twice on a coffee date. He wants to make me his second wife. Am I comitting zina in this case? Is he considered a cheater? Or is this okay since he says his intention is to make me my second wife?

Going on dates with a non mahram man is itself not permitted and can causes many ethical problems but still we can’t say it’s as an adultery as long as both of them had not have any physical relationship.
As for as the philosophy and condition of polygamy in Islam please go to the below link you will find your answer in a complete way.