Why I can't leave him?

Long story short:

- I caught him cheating, he said it's my fault because I checked his messages, I forgave him

- I caught him cheating again, sending messages to girls inviting them for a drink. I forgave him...again

- We got married

- Caught him cheating again, again...my fault because I was checking his messages (BUT I CAN'T FUCKING TRUST HIM ANYMORE)

again I forgave him, he said that it won't happen again.

- And again it happened...he's giving hearts to half naked girls on a lot of social media obscene groups (like real girls, not some pornstars photos posted by men)

WHY I KEEP DOING THIS TO MYSELF? I NEED HELP...