What is that reason? This isn't the middle ages and you don't need men to defend you from wild beasts or to provide shelter. If you want to say you're a precious flower that needs a white knight then that's your prerogative. But fundamentally in the modern age of technology height nor strength lends any advantage towards status or security.
Don't give humans more credit than we deserve, just because societies evolved thousands of years ago in a certain way and have remained largely static regarding gender roles since, it doesn't make it right.
If you'd like to show me some hard evidence that women are better suited to be unemployed and take care of children I'd be happy to take a look at the studies.
IT
HAPPENS ON A LARGE SCALE BECAUSE AS HUMANS SOCIETY HAS DEVELOPED THAT WAY. Women are weaker, so what? The large majority of work in this day and age does not require manual labour. Once again it's nuture, you pretty much feel like this because it's been ingrained into you. You might not like it but you've been indoctrinated.
Try and see things from a critical point of view and understand there is no legitimate reason for gender roles, and don't use anecdotal points please. 'men are the opposite of emotional' isn't proof of anything, it's just making up a point to ad hoc rescue.
As do most women
At least you're willing to admit if you prefer the status quo simply because of the advantage it lends you, unlike the above