I'd also call bullshit on this anecdote and most of the ones in this thread: the most common age of consent in the US is 16, not 18 and specifically, in Texas, it's 17, meaning that there are two different ways that this particular story doesn't add up.
So even if it's legal to have sex with a 16-year-old in Texas (under State law), it's illegal to produce, possess or distribute pictures of that child (under Federal law).
Also, the GP to this thread never stated that the guy would be a convicted statutory rapist for sleeping with his wife, but that he would have been a statutory rapist who's victim is the person who is now his wife.
There's plenty of ways this could have worked to the guy's disadvantage. There's really only one way it can be false.