My husband wants to adopt my daughter...how?

You say you were given FULL custody - does that include SOLE LEGAL CUSTODY? I doubt you were awarded that since you were married. Further, since you were married, and your ex's parental rights were never terminated, you can't have your new husband adopt the child. You would have to have the ex's rights terminated, which the court won't do if the ex contests the application.

A court would have to find it was in your daughter's best interest to have her biological father's rights terminated and to be adopted by your new husband. This will require a court proceeding, specific steps, and you would definitely need a lawyer to guide you.