I've been struggling with a problem I would consider a bit similar. Existential crisis or something along the lines of that. Purpose, meaning, value, etc. I went and spoke with a therapist for a year or so, I didn't need that much time, it was just an easy relaxing time where I paid (mostly covered by health insurance) a professional to listen to me ramble and received some answers on how to not be upset all the time.
I would recommend you possibly do the same. If not a therapist, then a religious leader (if you practice). Someone you can speak to without having to censor your thoughts or feelings. Many times they can help in different aspects of your life and help you find ways to communicate with your significant other or by being an intermediary between you two (marriage counseling).
Take some time off. One or two weeks, maybe a month. Set up a video chat thing with laptops to stay in touch with your children (and get in touch with them often). Experience a different way of life and see how other people have to endure the hardships of everyday life. Experience suffering first hand...it will give you an appreciation for the life you have around you. Also take time to enjoy life by yourself for a little while. Escape. Go surfing, skiing and mountain biking (can probably do all three in California).
As for your job, develop a hobby or research other parts of the world if you have so much free time. Porn and loose women are only a quick way to take your mind off of the problems you should be addressing sooner rather than later. They also tend to bring you further down rather than giving you actual happiness.
But in my opinion I think it would be cowardly to abandon your family. Taking the easy way out teaches you nothing. I've thought about throwing it all away but I would not be able to deal with how I would hurt all of those around me who care for me. Your family cares for you and I'm sure you're children would be devastated if their father got up and left the household never to be seen again. A neighbor of mine had his wife simply say she was done with the family and she moved to Arizona with her sister, leaving her entire life behind her. I don't know if she stays in contact with her children, but at ages 11 and 13 it can't be easy to live without a mother. Those years are confusing enough as it is.
This is something you can work through. You just have to bite the bullet and find the help you want. It all comes down to you.
I don't know what kind of music you listen to, or if you listen to any at all, but I've been recommending a lot of songs to people today for some reason. Perhaps you might like this one:
Atmosphere - "Modern Man's Hustle"