There's a couple different ways I could see a story going for this, but the first one I had was Dazed and Confused. Rich and Brynn are together in High School but break up sometime during the following year. Reasons. Rich is still in the area and hanging out with other people when he starts dating a new high school senior. She thinks he's so cool cause he's out of school and dating her, she must be special. He keeps this cycle going for a few years, dating high school girls, taking pics, and so on. He'll even take pics of women after sex when he's at the bar and whatnot. Where it comes to bite him in the ass is one day the girl he hooks up with isn't 18 but 15. Depending on the timing and if cell phones are a thing yet, her parents find out and Rich's ass is grass.
Another way this goes is "Hot for Teacher." Rich becomes a high school teacher. He's always seen as the cool teacher, but in reality he's hooking up with a student or two. Has been for years. One day, one of the girls he's hooking up with takes things a little too far and tries some Romeo and Juliet crap and blames Rich for her being in the psych ward. If you want to make him even more of a perv, drop the grades he teaches from high school to junior high. A twist on this is the crazy girl and Rich didn't hook up, but she sent him nudes anyway. When he gets investigated, turns out he had pics of other girls as well.
So a couple of additional things about Rich from real life. The reason why I saw Rich a few times up to the Super Bowl, but not after that, is that he and I went on to the same college, but Rich dropped out shortly after the Super Bowl. I'm thinking that Brynn was missing Rich and pressuring him to drop out and move back home. But when he did so, Brynn soon broke up with him and this left Rich angry and embittered--after all, he'd just dropped out of college to be with her, and then she immediately dumped him.
In real life, Rich may indeed have been planning to become a teacher. I'm thinking he probably transferred to a college closer to home, and may indeed have gone on to become a teacher. The news article about his being convicted of a sex offense says he was then a real estate agent. However--with all due respect to all real estate agents out there--I've noticed that sometimes people end up as real estate agents when due to a criminal background they can't pass the more stringent background checks involved in working with kids.
So I'm thinking that Rich moved back home, Brynn broke up with him, he became a teacher, but was forced to go into real estate after his first sex offense conviction. I also noticed that Rich is not actually a real estate agent in my home town proper, but in a smaller community about 100 miles away. I'm thinking he was driven out of the larger community to the smaller town nearby due to a bad reputation for the sex offense.
Basically I'm thinking that he must have been convicted of sex offenses twice. There is the one I know about, but I'm thinking since he was already a real estate agent then, there must also be an earlier conviction (that I don't know about) which forced him out of teaching and into real estate.
Where I'm going with this is that maybe he created a porn website for selected senior girls from the school, or recent graduates. At first he tried to keep it to those over 18--albeit barely legal--but gradually became careless and eventually got caught.
Another scenario is that he created the website but did keep it to those over 18. He got caught, but since it is no crime to show an 18 year old nude, he just got fired from his job as a teacher, switched to real estate, and moved to the smaller community where he was less well known. Without a job as a teacher to protect, however, he started to slide into more hardcore illegal stuff including child porn.
Basically there are two major events in Rich' life that cause him to become embittered and accelerate his slide into criminal activity: Brynn breaking up with him, and being fired from his job as a teacher.