For how long do I need to be married, before my husband can adopt my son from a previous relationship? I already have a 7 year old daughter with my current husband from before we married. My son is now 10 years old and I have no knowledge of the father's whereabouts since my son was 1 year old.

Where are you from and staying now?

You can apply for adoption at any time, but attempts have to be made to find the father, and that drags it out considerably. The court will tell you how to try to find him. I assume that he is listed on the birth certificate?