When Paul arrives in New York City, the secret is that he has stolen the money he is using to live the high life. It is more effective that we know, as we as readers feel the underlying anxiety surrounding all the glamor Paul is experiencing. We know Paul will have to pay a high price for his binge.
Paul could have chosen not to commit suicide, but it is hard to imagine him making this choice as it would have a meant a life of ugliness and hardship in prison. I would therefore have to say that suicide became Paul's only realistic alternative once he stole. The only way to have prevented it earlier would have been to put more beauty into his life or to have helped him increase his sense of self esteem, but my feeling is that unless he was living at the highest levels, Paul would not have been satisfied.
I can relate to Paul in some ways. Like most people, I am more likely to be willing to save and make compromises to have beauty in my life, but I can understand how miserable it would be to be constantly surrounded by ugly and tacky things. The question becomes, in terms of relating to Paul: how important is having the most glamorous possible life to you? I don't relate to Paul in that I have developed an interior life and a sense of self worth that is not dependent on looking vastly wealthy to other people: Paul might have been helped if he could have met someone before he stole the money who encouraged him to value himself more for the person he was inside, rather than what he could buy.