Ah, MGTOW... and my first post here.
I haven't read enough into MGTOW to understand their position entirely. I may fall into the category however.
There's the tendency to believe MGTOW types are simply people that can't get laid. Maybe this is because many can't understand why a man might refuse and be hesitant about the consequences of getting involved with a woman.
My being MGTOW/similar probably stems from my parents divorce. It was a particularly nasty one (I know all divorces generally are..). So, issues relating to my mother and her desire and ability to take advantage of the state which allows her to use the law as a weapon of spite.
The number of people I've come across that have been brought up under similar circumstances is rather scary. I think MGTOW may be a reaction to divorce laws (and laws in general) which unfairly punish men. These laws, at least where I live, presume the man is guilty before being proven innocent (and proving such is expensive). This is justified as "erring on the side of caution". The problem with this is that... when you give one group of people an advantage, they'll make the most of it. I'm sure you've heard it all before... the wife that claims abuse in order to get 100% custody and therefore a greater percentage of the assets.
I've had many relationships that ended up pretty badly. I've been removed from my home by police after being prevented from leaving a room, then being hit and yelled at (being male, I just had to take it). She even admitted to the police that this is what she had done and I was still removed. Due to mentioning "many relationships", I have to then look at myself and work out what it is that I might be doing to aggravate the situation.
I believe my problem is that I don't compromise on who I am and what I want. I think to a certain extent, women (and men) try to shape their partners into something contrary to their true nature. People fall in love with an idealized version of the person based perhaps off of what they desire according to the movies and dramas they've seen. It's almost as if people are living their lives according to a Hollywood script. They want the drama.
So, I'll be eating my dinner when all of a sudden my partner will come in and be "outraged" over something relatively trivial. What I'm meant to then do is play the part of someone who is upset, overly defensive perhaps... I dunno. I'm meant to react emotionally.. support the drama. When I respond rationally and keep my emotions out of it, I believe what happens is that I cause offense for not being more disturbed or enraged.
My former profession was as a "bouncer", so I know that you've got to keep your cool. If you let your emotions slide and respond with anger things escalate. I believe with the women I've known they require that anger in order to feel loved. If they can't rouse you to anger, what power do they have over you? It's similar when sex is used as a bargaining tool. Some/perhaps many men will fall for this. With me, I'll just say "I've always got porn". I have the tendency to automatically swing the other way whenever being given any kind of ultimatum. This infuriates people.. which is why I end up having the police called on me. I think women know they have that ace up their sleeves. Again, no proof required. All they need to say is that they have a fear of what "might" happen.
So, knowing the risks and having experienced injustice.... I have a fear of getting the wrong woman pregnant. I have a fear of getting emotionally attached to my children only to have them ripped away from me due to some one-sided law. I feel that the family unit has been compromised/attacked by government. It is not so much women that are at fault, but society at large. This isn't a world I want to bring children up in. I feel strongly that the way in which governments are gathering debt... the fiat money system has to at some stage crash. I don't want to be the guy from the movie "The Road", and as much as it may sound silly, I believe if I don't listen to my instincts Murphy's Law will come down hard on me.
If I don't want to bring children into this world, there's even less point in a relationship. I understand that in making that decision it's the end of the line for my genes and I'm fine with that.
As for the idea that MGTOW is financially unsustainable... that doesn't make sense to me. Being single I save far more.
It's hard to describe the "why?". Best I can say, it's instinctual.