Is a judge likely to terminate the parental rights to the father of my son if I am married to someone else?

I do not think the Judge will think it is in the child's best interest for the biological father's parental rights to be terminated in the circumstances you describe. A person "signing over his rights" is not effective unless the Court follows that with an order terminating the parental rights of the father.  In other words, it takes a court order to terminate the parent-child relationship.  One cannot simply declare oneself "not it." The Judge works for the State and the State wants the biological parent, who has a legal obligation to financially support the child, to be ordered to pay child support and provide health insurance and dental insurance for the child. Sounds like the father is in a good position to do that now. So that is probably what you should request if you want to counter a move by the father to have his own rights terminated. If you are requesting a termation of the biological father's rights and also have a step-parent adoption filed, the court is more likely to approve the termination, but also approve the adoption by your husband at the same time.  There are, of course, requirements you must meet before a step-parent adoption may be approved.