Although it's more difficult to control feelings than to control actions, it's good to try to let go of resentment as much as possible since it only poisons you and does not help anything. It is better to focus on anything practical you can do that is best for the situation (if there is anything), and if there isn't anything you can do, try to focus on other things. 
 

Sometimes as we make our way through life, we get a better understanding of the psychological reasons why parents act in a less than ideal way and can have compassion for that, even if their choices were harmful to themselves, ourselves, or others.