Agreed. Definite troll.
As you mentioned, he writes a big long post, but is ultimately vague about it. First he says a couple of stds, then one, then back to more than one.
His references to the post-nuptial thread also heavily leans in the troll direction. The whole warning to other guys thing. The idea that the girl was only with 3 other guys really supports this. This lends toward the whole instill the fear of God into you strategy. 3 people my arse. So, this guy is 40+, has evidently been around the block a few times and really believes this? I have a bridge to sell you pal. The reality is not that he believes this, he made it up. That is why it is so ridiculous.
To recap this guy's situation. He finds out he has one or more STDs and is so freaked out he feels he has to post about it on a message board. Yet the entire message of his post is "hey guys, you should definitely get married. there is so much more to cherish."
probably just got out of his american's for families sunday bible study class and is trying to spread the message. Didn't they talk about how you aren't suppose to lie in your little groups? Nah, probably just whatever it takes to convert huh.