Hi. I want to say this thing: a child is a separate person, with his own character, reactions and other human qualities. You cannot force yourself to love another person, but you must take care of him. You are an adult, and you must be responsible for your child, even if he was born from a woman who is now unloved. The child is not at fault.
In the same way, a child may not love you when he is a little older. No need to try to be what you are not with a child, he will understand everything anyway.
I got the feeling that you were simply afraid of responsibility, and therefore you are leaving for other, easy and comfortable relationships, where you can receive only joy and give nothing in return.
I’m not judging you, I’m just urging you to think about your actions and behave like an adult. Good luck!