Kussetsu

The best friend of a high school boy decides to destroy the perfect world around his friend by taking his stepmother, stepsisters, and female friends from him. Deceit, lust, and revenge are performed by all parties before it all crashes down. [taken from Anime News Network] Your reputation is in the gutter, but your best friend has the perfect life, even though he doesn't deserve it at all. This irritates you to no end, and you decide to take every girl and woman from his life, one at a time, to expose what he really is.