take a look at that for the 14-17 provisions. Apparently a parent can “consent” to the relations.
Texas also has common law marraige but forbids it to the under 18 crowd.
all at http://www.findlaw.com
As I originally said, I won't condemn anyone until the facts are all out. So if the parents give consent to either a legal or even spiritual contract between their children and another, this could all be within the confines of the law. I looked at some other material that indicated a three year age difference for parental consent to be consideration. That could well be the crux of the matter. I'm not a lawyer..I don't know. (What that says to me is..if a kid falls in love with her 18 year old boyfriend it's different than a kid falling in...whatever..with the 50 year old neighbor).
As far as common law marriage..I don't think you can be married, legally or common to more than one person.
Too bad the laws are written in such mumbo jumbo.