Kim and Kanye will have a prenuptial agreement before they marry.

Kim Kardashian and Kanye West have already agreed ... they will keep their assets separate by drawing up a prenup before they tie the knot ... TMZ has learned.
    Multiple sources connected with the couple tell us ... both Kanye and Kim are committed to the marriage and they are not signing a prenup because they're worried the relationship might fall apart. But they're both business people and know given their vast wealth it's just the smart thing to do to have a prenup. 

    Kim especially understands the importance of a prenup because her late father, attorney Robert Kardashian, told her over and over about the necessity of having clear contracts when it came to money.
    We're also told ... even though they will keep their assets separate, they will have a fat joint account for living expenses that will probably approach the gross national product of a small country.
    As for how much they have ... some reports place Kim's wealth at $40 mil and Kanye's at $90 mil. But we're told Kim's actually worth more than Kanye.
TMZ