Is it normal to struggle with a healthy relationship when all you know are unhealthy ones?

For the first time in my life I am in a healthy relationship with someone who respects me, and wants to take things slow to build something that lasts.

I am used to being in relationships that were rushed, abusive, and unhealthy. I have been cheated on and used.

This guy though, is awesome, and has done nothing to make me doubt him or his intentions and yet I keep looking for signs in his words or actions because I feel like it is bound to happen. I don’t let it show because I know that is crazy enough to push anyone away but inside I am so anxious about it.