Children are usually quite resilient. If the adults around them are happy, they feel good. You will have to decide what you want to do and after clear thinking, take your next step. Your daughter will make adjustments to your new partner, and perhaps keep her attachment to her biological father. In your question, you seem to be looking for reassurance and support for your decision to start a new relationship. When your daughter gets older, you can explain your own motivation and feelings to her. For the present, please be consistent, warm and affectionate to her. Even if she resents a new father for a while, she will learn to like him, if he is warm and friendly to her.