I hope you don't mind me sharing some thoughts. I don't want to come across as trying to tell you what to do but I hope I can be of some help. If you've read my posts on this thread then you know I can completely sympathize! I wish I had the definitive answer to your (our) problem but, sadly, I don't.
I have been married for over 30 years and have three kids. Very happy.
and
I absolutely love my wife and my family - everything about it
This is what's important. I think you need to come to grips with the fact that, as much as your desire to play with a man's dick is driving you up a wall, it's just not going to happen (or at least it shouldn't). I know full well that's easier said than done. I think you know in your heart, though, that it's not worth sacrificing the beautiful thing you have with your wife and family in order to satisfy your alternative sexual cravings.
That being said, I would suggest that you try to stop dwelling on your desires and stop masturbating over them, You're just feeding that bad dog.
I have a lot of free and private time to peruse those sites and communicate with other men who are similarly curious.
I used to do that as well but I've forced myself to stop. That's just more feeding the bad dog. I've accepted the fact that I'd love to play with a man's fun parts and that will probably never change. This site has actually been quite helpful to that end. These desires still pop into my head but I've now created boundaries for myself that I know I can't cross.
Also, my wife has no desire for sex either. I've talked with her honestly about how the lack of intimacy in our marriage has had a serious negative affect on me and that I really still desire her physically. It wasn't just one discussion but more a series of discussions. She seems to understand and, though It may not be the hot sex we used to have, she will "occasionally" give in to my playful "begging" and she usually winds up enjoying it. This doesn't necessarily stop me from thinking about playing with a man's privates but it does help keep me from obsessing over it.
Like I said, I don't really have a "solution". We're all individuals with our own unique set of circumstances and we'll each have to find our own way to cope with our issues. I don't understand why we have these same sex desires but I do think it's natural. That doesn't mean we should act on them but I don't think you should feel guilty just for having the temptation.
And there's one more thing that has helped me and that's prayer. I don't know where you stand on that but I would be remiss if I didn't mention it. (I know that can be a whole other discussion in itself)
In any case, good luck. I know you can win this battle. As Jerry Seinfeld once said (more or less), we can all be masters of our domain!