Honestly it just comes by having few options and being in proximity of woman with high fecundity. If you can land a girl in bed and convince her to procreate with you, and she is 10x hotter than any chick you could realistically bang, why would you let her go?

Of course, none of them are realistically looking at the situation, which usually amounts to the woman at hand using them as an emotional tampon, a walking atm machine, or both. Methodically stringing the guy along, hinting that he may have some chance in hell of one day banging the shit out of her, even though he doesn't and never will.

It's caused by blue pill thought

I don't think it is. It's caused by us being a species that evolved the trait of high male parental investment (fatherhood).

Basically, once you've pair-bonded to someone, emotions tend to run high - if she returns the investment in you, it's all good. If she doesn't - it can be extremely painful.

Oneitis is fine, if she has it for you.

But at it's root, it's all about mate-bonding so you can be good parents together.

*Mary Jane Rottencrotch.

FTFY

insecurity, they don't want change and even more they don't want the possibility of rejection

Common story theme are of a guy finding his "true love, the hero finally getting the girl he always wanted, or something along the lines of someone getting "lucky" because they met a nice girl.

Guys get the idea in their head that if they meet a girl they connect with it means she's "special" and he should marry her as soon as possible. They think it'll never happen to them again or they don't wanna risk loser her and never finding another girl again.

A romance for a man has traditionally been less fraught with dangers for a man (pregnancy for example), thus they're more prone to idealistic dreaming rather than careful, callous calculations.

Men want women to bare their offspring. I don't think it's a tendency for oneitis, though men who are unsuccessful with women will likely exhibit that behavior, I'd argue it's a tendency to ensure that women don't sleep with other men. You will see it with a man who has one wife, you'll see it with a man who has ten.

What is the difference between oneitis and love?

Lack of having an Abundance Mentality. You think she's the best you can ever get so you start rationalizing a lot of crap away and compromising your life goals, beliefs, and dreams for her.

Apathy for me mostly.

We've been lied to all our lives about romance and women.

So when we feel we've gained a nice woman's acceptance and attraction, we fall face forward into reality when things don't go the way we day dreamed about

We don't assume women can flip-flop on their decisions and monkey branch, because we've been told that it's men that lie and can't commit to their romantic agreements.

And then we grow up. Some never get to though.

You know what? This is the only place where I can go read a chain of comments and see so much of an idea explored regarding women. We are certainly getting there as a group gents.

To your point OP:

I had oneitis for seven years. http://heartiste.wordpress.com/2010/09/21/curing-oneitis/

That email was mine.

Having moved past it some time ago I can tell you like anything emotionally compromising it is a question of how much space it takes up in your head.

The first girl you date is going to fill most if not all your sphere of thought related to women. As you date progressively more you will begin to realize the spheres currency of expansion isn't an amount but emotional residue left by each interaction. An either enjoyable recollection or a little agony it literally doesn't matter to your brain, it gets stored with equal anticipation as value.

If the first girl in my case hits you significantly harder then other women but she isn't worth keeping then you are stuck in a bind. This situation leaves you rating potential mates lower because they cannot claim as much of that sphere as the other girl and then you get the rare to be seen male hamster spinning with thoughts of I can just do better then this etc.

That's the flipside of oneitis, its N-itis. I went from one to infinity. Not yet discovered by the red pill community, it is indeed a thing. Its the complete reluctance to give a girl of reasonable quality any space in that sphere. It comes from a disconnect in arguments such that the things you are looking for in a girl do not sufficiently create openings to your mental sphere making aligning with someone harder then it is supposed to be for them in a way that causes a deficit in the interaction. (Think like a longterm overnegging of someone to the point where you get the hard N rational NO coming out of their mouths.)

Over time you end up thinking of women entirely as sex objects instead of people. This is what feminists get butthurt about. They get butthurt about it for a completely different reason. They arrive to this conclusion because all the womanhood they have left is in between their legs.

You have to take the time to create space for them to occur as contributions in your life. If you want someone who knows how to act in front of your friends, there are flags to look for. If you want someone whos going to let you play games and not have their pussy dry up theres flags to look for (chances are they have no clue what MAC makeup is) but really the disconnects come down to this:

Oneitis occurs when more goals either conscious or unconscious have been achieved by a girl and you have no close contenders and you let that create your interaction with that person instead of the pursuit of your goals. It's getting lost in the thrill of victory while the battle is still being fought.

N-itis occurs as a form of upset that comes from the perceived reality that your NAWALT girl so to speak doesn't exist. You fuck random girls then begin to step out of the game completely.

They don't exist because you haven't created the space for them to occur in your life yet. You haven't put the thought or effort into what you would give to them in order for them to get what they want also.

tl;dr - men get oneitis or n-itis because their sphere of thought related to women is either too vulnerable to one person or not vulnerable to anyone and it comes from not taking the time to create a space for them in your life.

edits: spellcheck is the online dating of the english language

She became a part of your identity but hypergamy prevents that from being a lasting condition for her. She jumps ship, you're devastated. You lost a part of you, but it was just the feminine imperative for her.

Your defense is to spin plates and avoid complete commitment. You don't innately have anything like hypergamy to back you up, but with proper training and refinement you can ensure you don't get burned anymore.

Could easily be biological not logical.

i've "taken the red pill." i'm a realist when it comes to relationships and girls. i'm also quite good at picking them up.

but you know what, i believe in love, and i imagine most guys do. i'm not so sure there's an eternal love (but it'd be oh so nice if there was), but i believe in love. i'm not expecting to, but i hope i'll find a girl out there that makes me change my mind on marriage and settling down. there are probably quite a few girls out there that i could love. i know girls are biologically-inclined to hypergamy as guys are to spinning plates, but i also know that there are girls and guys out there that will be the exception to these biological imperatives we have for certain other girls and guys. and if they're so lucky to find each other, they'll stay together till death do them part. what, you haven't seen an elderly couple still very much in love? get out more.

so, what's wrong with oneitis as long as you don't turn into a beta when you have it? are you really going to avoid falling for someone because you don't want to have your heart broken? you can do that, but me, i'll take that risk to have a chance at the reward.

Because they seek approval and validation. There is a hole in them that they cannot fill, and they find it with a woman [or many women in succession.] You can see this because sometimes they will actually get the girl, smother her in gifts, affection, and love over a period of time, and she will run away, cheat, or break up with them.

You cannot find approval in women. You cannot find approval in other people. Even if they somehow did manage to give it to you, it will not fill the hole.

You must find approval and acceptance in yourself.

edit: whole/hole

It's caused by blue pill thought

Don't fall into the same trap that feminists do. Not every impulse you find objectionable is the result of societal conditioning. Most are the product of human nature.

Human beings are semi-monogamous. We have a natural desire to form pair bonds, as those help in the rearing of our children. This is where oneitis comes from. We also have a natural desire to deversify our genetic porfolio. This is where polyamory and cheating come from.

Every human being on the planet is a mass of conflciting impulses. It's part of what makes us so adaptable as a species. I also makes it important to rememebr that there are times when your instincts will betray you and lead you to do things which don't make you happy in the long run.

Part of it is cultural programming to heap virtue on the feminine. this leads to putting pussy on a pedestal.

Part of it is scarcity mentality.This leads to obsessing over one woman. aspergers may play a hand in the obsessive aspect as well.

What I find interesting is how guys with options can still get oneitis, in some cases not even for the best women of those available to them. Usually in the cases I've witnessed it had more to do with ego protection from being rejected.