I originally wrote this as a reply in another thread, but it didn't quite fit there, so I'm putting it here instead..
You built a harem..
You know those science fiction comedies where a couple of teenagers somehow build themselves an ideal robot woman in their basement and fall in love with her? PMO is like that, except that it's just one guy, and he's built himself a whole harem of unfeasibly hot women.
So when this guy goes outside of his basement, in the normal world, he is not interested at all in the normal women he sees because he's got a harem of uber-hot women back home. Getting back to them as soon as possible is all he can think about.
Just like those kids in the movie, we have fallen in love with that harem. It is as simple as that. Your brain thinks the harem is real and is behaving accordingly. When you are at home, you are desperately excited to bang girls from your harem. When you are away, you are excited to get home.
You have to break up with the harem..
This process is so tough because it involves BREAKING UP WITH THAT HAREM. Your brain has to accept that you are saying goodbye to all those girls, never to see them again! Your brain fights you for 8 straight weeks, because IT DESPERATELY WANTS TO KEEP ITS HAREM. It will make you sad, angry, miserable, depressed, horny as hell, numb, null - it will drag you through the worst kinds of hell it possibly can to get you to go back to your harem, because it loves them so much. Look at my mood charts - my brain put me through horrible bullshit for 8 straight weeks.
But then, just like when you break up with a girlfriend (well, in fact exactly the same because it is the same), you wake up one day and the fever is gone. The brain says "OK. I get it. *sniff*. I guess they're really all gone and I'll never see them again. *sniff*... Hey - that woman waiting in line at the bank is cute though! Hey baby!" And you are healed. You are back in real life, and you have no magic, robotic harem at home.
I will share something embarrassing/amusing but also really important with you. Exactly a week ago, I had massively strong feelings of missing - you know those feelings you get after a break up with a girl. There's a song that kept playing in my head, that one that goes 'I ain't been missing you at all - no matter what my friends say'. I played it on youtube, and listened to it on headphones. I cried for two hours straight, playing it over and over, while memories of all the girls I liked in all the porn I'd seen over the years - my favorite girls, the ones I felt closest to - scrolled around in my head. I was saying goodbye to them. It was like looking through photos of you with your ex-girlfriend after she broke up with you. So yeah, I cried for two hours, maybe more doing that. Afterwards, I felt a huge sense of calm, peace, closure. They were really gone. That night out in bars I got 3 numbers, and went out on a date with one of the girls I met the next day.
Eventually, your brain accepts..
So when you ask if it's hard to continue to not PMO. No - it's really really easy. My brain knows that those girls are gone. It has accepted. It has given up trying to make me go back to them. It has moved on. Now when I'm at home, my brain knows there is nothing sexual there at all. When I go out, my brain knows there are fine women around that it might want to get with, but that the only way that anything sexual will happen is to have sex with them, because M is no longer on the menu, no longer an option.
But it takes 8 weeks to get to that point. In the meantime your brain will be screaming bloody murder. And sometimes it stops screaming, but it's only so that you get used to it not screaming so that it can shock you even better when it starts screaming again.
That's also why I say cut out TV. If you're at home, and a fine woman comes on the TV, your brain says "Hey! There's a girl from my harem! I guess my harem didn't disappear after all! Hummana-hummana-hummana." And you get all excited again. Home has to be dead of women to you. Nothing there. No glimpses, no faces, no bodies, no nothing. World outside - women. Your home - boring as f*ck. That's the only way your brain gets the message it needs which is that the harem is no more. Gone.