This isn't a story, but the webmaster stated that the reply should be sent as a story
I'll try to answer your questions about male masturbation first, then give an opinion, which you should take as being nothing more than one person's ideas on your problem. But I am older than you, and am married and not a womanizer, so that may give you some perspective.
First, your boyfriend's obsession with masturbating is perfectly normal, as a review of the contributions to this site bears out. It is also normal for men his age to be greatly turned on by women and girls of the ages you mention. It is human biology in action: some men are more easily turned on than others, but in all it is only a matter of degree. Since he confines his response to masturbating, as I and countless other men do, he is not sick nor a pervert.
Having said that, I would be willing to say that he is not very considerate of your feelings if he continues to make a show of eyeing other women and girls so that you would notice it. Likewise, unless he is a computer illiterate, he should be able to cover his tracks from his computer voyeurism so as not to rub your nose in it, so long as it bothers you. I don't think he should promise to stop either of these activities you dislike so, as he probably can't. Nevertheless, he COULD avoid doing things he knows will irritate you. In this sense, I can see why you might call him a pig, though insensitive is more like it.
Now, as to your responses to this-- they are mostly learned, and you would be a happier woman if you could do some un-learning. You clearly enjoy sex, so the problem is not physical, or even psychological frigidity. You just have some ideas that make you see rather normal behavior as evil.
What you think of as a MORAL position is really an AESTHETIC one which you have elevated to the realm of morals.
Masturbating is not immoral. Quite the contrary, it is one of life's greatest pleasures. I do it all the time, especilly when reading the contributions to this site, but the site of women is enough to get me going. My wife isn't interested in mutual masturbation, so I do it in private. But if you were to bring yourself to ask your boyfriend to jack off for you, you might even like it, and maybe even be moved to masturbate for him, as well. Watching a woman masturbate is one of the greatest turn-ons most men can experience.
My first great experience with sex with a woman came after many years of solo practice, and involved mutual masturbation with a lovely young woman who preferred masturbation to vaginal sex. So we had the most torrid affair, getting each other off in every other way conceivable. I still get very hard just remembering it.
So maybe you could redirect your boyfriend's love of masturbating from others to yourself and find that your sex life will be greatly intensified. What do you have to lose?
Best of luck to you. Easyrider