Ready to leave

Ready to leave a an abusive relationship with a narcissist I just don’t know how to I have 3 other kids from previous relationships & I’m currently pregnant now ready to go can’t deal or process with things anymore it’s gotten out of hand I should’ve never even let it get this far I wanted to try to stay for the kids for my unborn but I really can’t see this working out long term I’m ready to move on in life no more kids no more dating just focus on my kids I have now and giving them the best of me I need advice how do I leave ?