Sorry, but Ahab does have a wife and son back in Nantucket, and they are mentioned several times in the book. Reread chapter 127; when the Pequod meets the Rachel, the Rachel's captain begs Ahab to help him look for his son's lost whaleboat. The captain appeals to Ahab by reminding him that he (Ahab) has a child "of his old age" back in Nantucket.
Also, in the past twenty years or so there have been many scholarly papers published concerning homosexual themes and imagery in this book. Just Google Moby Dick homosexuality.