Legal Question in Family Law in Texas

Simple answer: you're right, he's wrong--tell him he's a loser and needs to to go away. From what you describe, no, he does not have a leg to stand on here, and honestly, I very seriously doubt that he would pursue anything legally. He knows the relationship's falling apart and he's desperate to stop you from leaving him. Which, ironically, is a pretty good indication that it's time to get out.

Unless you have some kind of significant assets that you're afraid he might try to claim, or if he has debts that you think he might get the bright idea to try to make you responsible for by claiming you're married, or youve been together more than 10 years and he's unrmployed and might try to get spousal maintenance, I really wouldn't worry about it. Even if you have a child together, regular marriage, common-law marriage, or no marriage doesn't really change much there, assuming he's the biological father of the child.

Should it turn out he's really crazy enough to try to pursue this, the only ways I can think of him being able to do that are 1) actually filing a divorce petition against you, in which case you'd have to file a response saying that the case needed to be dismissed because there's no marriage, or 2) if he's really, really off, I guess he could wait until you marry someone else, if that ever happens, and try to get bigamy charges filed on you--which would not go anywhere without a nice piece of official paper proving you were married.

If you're really concerned about it, though, and you are actually still living together now, I'd think about what he might have lying around the apartment in the way of applications, etc. where HE has recently stated on paper to a bank, credit card company, current or potential employer, etc., that he's single. You might also consider getting affidavits from people who know the two of you well that they've known both of you for x number of years and they've always believed you were just boyfriend/girlfriend, have heard you refer to each other that way, and have never heard anyone say you were married. But my guess is that this is just his last ditch effort to keep you from leaving, and that maybe it's a sign that you need to do exactly that. Someone who would try to claim that is not healthy and is not someone who's concerned with your best interests. Good luck.