we have not lived together in 3 years - married 4 yrs ago - no contact
Should be pretty easy, assuming you haven't acquired significant assets. You have to file a petition, serve him with it and at the very least, execute a final decree (if not go to a final trial).
If you don't know where he is, you're going to need to do service by publication or track him down.
I'd recommend consulting a local attorney.
Abandonment as a ground for divorce will only be complicated by the existence of children and assets/debts. If the aforementioned do not exist, then the process will be short and not overly burdensome financially. However, if the above mentioned items do exist, then the process could drag out for some time. Contact a family law practitioner in your area or call the Texas Bar Association for a referral.
Based on the facts you should not have a problem obtaining a divorce. If you don't know where he/she lives you can serve by publication. A lawyer will best determine the grounds.