West is currently expecting his first child with the reality star.
"Kanye has real money. He won't marry Kim because it would hurt his finances. Kim is a shopaholic! She spends USD 350,000 a month on her credit cards.
"She pays hundreds of thousands of dollars for designers to custom-make clothes for her, and she spent millions on Louis Vuitton handbags to match each outfit," a source said.
Kardashian recently reached a divorce settlement with basketball player Kris Humphries, to whom she was married for just 73 days before they separated.
It has also been reported that a rift has developed between the stars due to West's insistence that their child be born in France, rather than in Los Angeles.