Ttc in a new relationship

Does anyone have a toxic relationship from the past that still affects your mind and the way you worry about how things will go?

(I’m happy and in a loving relationship now but I still feel scared of repeats with bring another child in to this world I have 2 kids already from my toxic relationship)

Any tips to help me better distress my worry’s (yes he reassures me but I feel like I need something for myself to reassure myself)