Maybe the bio will cooperate and give his blessing to avoid 18 years of child support.
My name is Stephen R. Cohen and have practiced since 1974. I practice in Los Angeles and Orange County, CA. These answers do not create an attorney client relationship. My answers may offend I believe in telling the truth, I use common sense as well as the law. Other state's laws may differ.. There are a lot of really good attorneys on this site, I will do limited appearances which are preparation of court documents it is , less expensive. However generally I believe an attorney is better than none.
You must terminate the parental rights of the biological father before your husband can adopt the child. A petition for adoption by a stepparent is typically joined with a suit to terminate the parental rights of the other biological parent. Frequently, the other parent has consented to have his or her parental rights terminated. However, your ex can certainly fight it. Terminating parental rights is not something courts do lightly and you must have compelling grounds--proven by "clear and convincing" evidence--to terminate parental rights. Your ex's failure to support the child and apparent abuse of you and the child could, depending on the facts and evidence, constitute grounds for terminating his parental rights. If he does not consent to have his rights terminated or you are otherwise unsuccessful in terminating his rights, then you can certainly go after him for child support. To do this, you will need to file a suit affecting the parent child relationship. The court will require your ex to produce copies of his tax returns, pay stubs and any other documents evidencing his income for at least the past two years. He will have to pay 20% of his net resources in child support to you (usually on a monthly basis). If you decide to initiate any legal action against your ex--particularly a suit to terminate his parental rights--you should retain an attorney.
Attorney Carrasco has provided you some great general info, which I would not add to. It is always advisable to consult an attorney regarding your case specifics.
This is not legal advice. This response is provided for general information only, as a public service. It is not to be relied upon as legal advice and does not create an attorney/client relationship; nor is it an attempt to create an attorney/client relationship. Consult with local counsel in your jurisdiction about the specifics of your case, which is the only way to gain true meaningful legal guidance and/or representation.