I can't help but hate my stepchildren and their bio mom.
That's horrible. Why do you feel hate towards your step kids and their mom?
She never listened to me, she always took my husband's side and she's a lazy bitch.
This sounds like a stressful situation but you all are family now. It is important for you to try to get along with your family.
Screw that, I hate that bitch for interfering in my marriage.
It can be hard to deal with your partner's ex but it seems like she will be in your life for a long time because they share children. So it is better to try to get along. Otherwise you will have a lot of miserable years ahead of  you.