I know people who are so dumb, that although you forgive them and put up with them, they still do dumb shit that harms you, so it is best to leave them. Leaving someone is sometimes best for everyone. I vaguely remember Buddha saying one should stay away from bad people, it is not weakness. Instead of hating them, you feel sorry for how stupid they are, but it is just impossible to help, it always gets worse if you try.