How does the fact that he's giving some of the money to charity affect your purchase in any way? Do you also feel bad that he's using some of it to pay his employees and care for his children? Would you be happier if he bought a hovercraft or something?
The value of the thing you bought doesn't change no matter what he uses the money for.
As long as he's not like, using it to fund terrorism or something. Then I could see being upset that you supported him.