New dad, positive and constant f

You most likely will have no real choice, if he either has a court order or is willing to go to court for one.

Next she does not have a new "dad" she may have a step father, who is a great role model in her life, and the deadbeat may not deserve the time of day. But he is still the father.

Next it sounds like he is wanting contact with the child. And him paying or not paying child support is not connected to his rights to visist

Also it appears you may have not actually asked or given all the info, come back and answer your own question to add more info

Why is the bio dad being called a deadbeat?