First of all the details provided are incomplete, whatever, things viz. cruelty, living separately (desertion which mean no relationship in any form) etc., could be ground for divorce, but it has nothing to do with your question relating to validity of marriage, for that you need to intimate caste status/ age of you both at the time of stated court marriage. Only thereafter, status whether said marriage was proper or void could be clarified. Presumed if marriage solemnized in marriage registrar's office viz. ADM etc., etc., same was proper provided you have not submitted forged age/caste documents etc., etc.,
Presume, governed by Hindu Marriage Act, obtaining divorce is not a easy thing, even in mutual divorce petition under Hindu Marriage act, it takes at least 6 to 18 months, otherwise things could linger on for years, mean in case you file a divorce petition your husband can file petition under section 9 of Hindu marriage act,1955 seeking restitution of conjugal affairs. So, cool down, take a mature decision, in consultation with concerned one.
Best of luck.
Me, Law Graduate.