Legal Question in Family Law in California

It depends on whether you and your husband adopted the child together or just you adopted the child. In the eyes of the law, an adopted child is exactly the same as a biological child to the parent(s) who adopt them. So if you adopted your nephew together as a married couple, legally your husband and your legal rights are exactly the same as if he was your biological child and your husband would have all the rights to seek custody and/or visitation that would go with that. If you had adopted your nephew before marriage, or somehow and for some reason adopted him just by yourself while married, it would be the same as if you had a child biologically before marriage - your husband would have no legal rights at all in most cases, and only limited rights in some special circumstances.