It all depends on whether the couple is still together. If they are, there is no point in arguing—they can manage the money together. However, if they are separating, it would be fair, as a sign of gratitude, for the man to give the woman a portion of the winnings since he took her money without her consent. If they were husband and wife, then without a doubt, the winnings should be split equally, as family income is considered joint property and should be fairly shared between spouses.
I bet they are separating or separated after the man won or else splitting will not be an issue to them.
I think greediness kicks on to both of them when the man told the truth while the woman demanded for a split profit. You’re right that they can simply live together and live a happy life with their money since that’s already to huge to spend for the rest of their life.
This shows how money change the perspective of each person.
Money could change a person instantly specially if we do speak about millions then this would be ending up on that argumentation or even ending up on file some lawsuits or whatsoever or correlation into it.