Well, I guess it doesn't surprise me that Texas would accidentally ban all marriages in a state constitution amendment that was intended to discriminate against gays and lesbians. The language from the ballot is as follows:
"The constitutional amendment providing that marriage in this state consists only of the union of one man and one woman and prohibiting this state or a political subdivision of this state from creating or recognizing any legal status identical or similar to marriage."
A quick grammatical breakdown of the language shows two separate clauses. The first one describing the definition of marriage, then the second clause says that such unions and anything like them are not legal in Texas.
Now, if that isn't bad enough, when I read this amendment, I would argue that does not ban all marriages, but really, if read literally, it only bans straight marriage. Since the first clause describes exactly what marriage is ("only of the union of one man and one woman"), and then bans things "identical or similar" to that definition, I guess two men could get "married" if they called it something else.
Way to go Texas! You might want to get a handle on the English language before you start passing any more amendments to your constitution.