Hi there and welcome to the clan. It’s an awful blow to realise your partner had advised you. It’s hard for a good person to understand how someone’s could deceive them this way.
There are some good books to help you understand why,they might help you a bit. Why does he do that by Lundy Bancroft and living with the dominater by patricia Evans. Have you looked up trauma bonding and how it affects you.
Don’t be so hard on yourself, once you have some more information and read the ladies posts on here, you’ll get stronger.
Leaving an abusive relationship is like a death. You have certain stages to go through with bereavement before you learn to accept the loved one had gone, it’s the exact same process with leaving abuse behind.
Take care, you will get there.
IWMB 💕💕