This has come up before so I copied a post below I wrote in January that covers some of what you just talked about. But one thing I didn't mention is the issue of grip. Yup, the old death grip on the cock that most men don't even realize they're doing when they masturbate. You probably don't even think you're doing it, but stop yourself sometime and relax. You'll probably be surprised to see how tight you're gripping your penis.
There isn't a vagina in the world that can compete with a man's hand because the muscles simply aren't as strong and can't provide that much friction. And as we all know, a condom just makes it worse because it eliminates nearly all the friction (that you've gotten used to) since there's little relative motion between the penis and the inside of the condom.
Once you get acclimated to masturbating for an extended period of time, and tolerating that much stimulation, it's very difficult to orgasm with anything less. So you not only need to reestablish your sexual arousal pattern to respond to real women, as LG stated, you probably also need to regain the sensitivity you once had.
And just as a word of caution, you can also lose sensitivity from wearing tight pants or underwear, and riding a bicycle or motorcycle due to the constant rubbing and/or vibration. There may be other causes too, but I've experienced this problem from all three, so I've got to believe other men have too.
I don't know your situation, but IMO any young guy like you should give the DVD player or computer a rest and focus more on dating real women. It can be tough for a lot of guys, but it will be worth it in the long run- and sex is only one reason. It will also help you develop your social skills and be more confident around women.
January 2010 post:
I think the incredible abundance of readily available, customizable porn, is creating a problem different than what might be called "traditional" porn addiction or sex addiction. It's crossing over to create the "atypical arousal pattern" for many men because recession or not, most men will never be able to afford real women as often as they need or want sex. Now this has always been the case, but in the past there wasn't an easy way out- now there is.
The unusual behavior that I think is emerging is that internet porn is so easy (the definition of instant gratification) that an entire segment of men is taking the easy way out and substituting it for interaction with real women. In other words, they're no longer trying very hard to have sexual relations simply because it requires so much effort, along with risk of rejection, expense etc.. Or stated another differently, they take the easy way out because it's easier to turn on the computer than it is to turn on some woman you just met- and it takes far less time invested.
Here's another unintended consequence of on-demand, 24/7 porn availability, and it has a name in business- mass customization. The fact that a guy can pull up any, and I mean ANY, type of porn to satisfy his craving du jour means that he gets conditioned to expect exactly what he wants on a given day. As a result, he eventually gets conditioned to respond only to what his craving at that moment.
From small tits, to teens, to Japanese bondage, to upskirt, to oral, anal, facial, or lactation, it's possible to satisfy absolutely any whim that pops into a man's head in a way no 10 women could ever do.
So why is this a problem? Because it makes it even more difficult to respond to real women that you meet while (attempting) to date. If she's not exactly what you're looking for you just move on. You no longer feel the need to make any effort to compromise a little bit, like millions of people have always had to do in the past as fantasy crashed headlong into reality. And the reason you don't is because fantasy is waiting for you back home, no matter how things went at the club.
The girl at the bar may have been too short, or didn't have nice enough breasts, but the ones online are perfect. The girl at the bar probably won't do anal, but you can experience as much anal as you want online. In small doses, this wouldn't be a big deal. But the phenomenon I think we've uncovered is that many men are way past small doses, and it's now creating real problems with the relations with the opposite sex.
If I were a sociologist, I'd research the heck out of this one before it becomes widely recognized. This subject may be somewhat of a surprise to women, but the men on this board know what I'm talking about.