Hmmm, shudaknownbetter,
Maybe this is another shuda-coulda-woulda issue? Unfortunately I don't agree with you that you "wasted these years." I'm much too much of an existentialist for that, LOL. On the contrary - I think you learned a whole lot from the experience, although maybe the lesson learned may not have been entirely up to your standards - or those of "the community," as it may.
I'm also much too much of a realist to look deeper into the issue of why you see providers. For whatever reason not described in your posting, you see many failures in your life, your first marriage being one of them. But you did find your present wife and have been with her for 18 years. That's a loooong time to have sex with the same person over and over again. My bareassed opinion on this one is that unless the other party is a helluva tigress in bed, attention will wander. That's totally normal. As to what you do with it is a different story. Some men masturbate to porn, others have affairs, some go to escorts, some just suffer in silence...the list is long and exhaustive.
I'm just trying not to confuse apples and oranges, that's all. If you had no sex drive left, this wouldn't be an issue, since you seem to appreciate your wife for many non-sexual reasons. But sex is one of those issues where many men run into a wall, no matter how happy their marriages are. Women, particularly after 18 years of marriage, are simply not biologically primed to continue having as much sex as men need. It is almost a physical impossibility. I just wish society would acknowledge this fact, rather than pushing the idea that women are as horny as men, particularly when it comes to sleeping with the same one over and over again.
As to experiencing new and interesting things with providers, well, that depends on what those interesting things are. If it's sex we're talking about, yes, then you probably will have some fun exploration to do. If it's deeply philosophical matters or brain expansion, then I guess it will depend on the provider. Of course, if your interests are purely cerebral, then you could just join some kind of association or take trips or do other things.
As to your neurological condition, that is surely unfortunate...but, as long as you're alive, it needn't be all doom and gloom. And of course, most professional providers won't be bothered by it, they've experienced men with all sorts of conditions.
It seems to me that you are beset with regrets and feelings of personal failure. My advice is to join a men's group or seek some personal therapy if those feelings become overwhelming. But, I also believe that wanting to experience exciting sexual situations is entirely NORMAL...particularly if you're like most guys who have had to put the breaks on their almost limitless drive for the good of "societal morals" and "community standards."
Here's hoping you feel a little better,
the Love Goddess