"Also there are studies that women tend to underestimate their skills while men tend to overestimate them which might also be relevant."

In general, men have far more pressure to be confident than women do.

This is actually a very important point, I work so hard currently because I know I will have to secure my family's financial future after I get married.

On the other hand, If I were to be a girl I would be a lot more relaxed in may approach because I know my earnings are not the primary source of income to my family. And husband is going to take care of it anyways.

Meh, I think most of the 'pressure to act confident' has little to do with wages and a lot to do with social mores. I have worked with many people over the years with much less confidence than I have who managed to out-earn me.

I've met more women who would prefer a relationship with a confident man who earned less than they do than I've met women who would prefer a relationship with a less-confident man who did earn more. I mean, that's all anecdotal, but I've been both (comparatively) wealthy and unconfident, poor and confident, and wealthy and confident, and as far as I can tell, the comparative level of wealth involved has little to do with dating outcomes.

On the subject of being out-earned, with traditionally male jobs falling out of favor and traditionally female jobs rising in importance and pay, it seems that us men may not end up being the primary provider for our families[1]

this is consistent with my observation both of the lower class and the upper middle class people I know.

[1]http://www.time.com/time/business/article/0,8599,2015274,00....