It's because you endured a lot of gaslighting from him. Gaslighting is a key component to abuse.
https://www.talkspace.com/blog/gaslighting-in-relationships-signs-how-to-spot/
https://www.mindbodygreen.com/articles/what-to-do-when-youve-been-gaslighted
Please work with a trauma-informed therapist if you can or attend a DV support group for help.
Here's how to break the trauma bond as well: https://www.harleytherapy.co.uk/counselling/traumatic-bonding-break-trauma-bonds.htm
How to recover from gaslighting:
https://www.talkspace.com/blog/gaslighting-in-relationships-signs-how-to-spot/
https://www.mindbodygreen.com/articles/what-to-do-when-youve-been-gaslighted/
Do you have a trauma-informed therapist on your side?
Healing is hard, but we don't have to do it alone. <3