not to tell you what to do, especially since i don't know a thing about your life, but magick shouldn't be used as a tool for revenge. make up your own mind about it of course, but there's enough hatred in the world, we don't need revenge crazed casters. like i said though, it's your choice, just think before you do, spells can backfire, and i know plenty of people who work curses. while there lives aren't miserable ones, they do see their share of bad things. [sickness, miscarriage, divorce] just be careful what you wish for.
also, magick has no colour, only intent. i understand what you mean, but it's 'positive' and 'negative' not 'white' and 'black' since some people can see certain 'good' spells as 'bad' and vice versa.