So why did you forgive him?

I find that when I have trouble leaving a toxic relationship, it's typically because I am unhappy in my own life and I am desperately trying to hold onto some semblance of love and happiness. Even if the relationship is toxic to me, it's functioning as a lifeline to save me from my own unhappiness and misery.

So how do you stop being a doormat?

You finally get to get to a point where you say "enough is enough" and "I deserve FAR better than that". Then you don't settle for anything less than what you truly deserve and want from someone, even if it means being alone and putting up with loneliness or unhappiness.