Theresa, Thank you for your message. First place to start is by writing down information you can get from your husband. Where was he born, and when, who were brothers and sisters. Get names of aunts and uncles and cousins. Get same information for his parents and also grandparents. With this information you can then contact vital records of the states here in the US or can write for a copy of a birth certificate if in Mexico. As you go earlier than the 1830's you can find information on the Mormon web site (www.FamilySearch.com).
My Maternal GrandMother, Maria Francisca Plasencia, was from Mesquituta,near Moyahua in southern Zacatecas, Mexico. It appears that the family originated from either Coquio or Ixtlahuacan, Jalisco which is about 50 km to the south.