All I really know is that all of the women I've known who told me they wanted "manly" men went off with arrogant jerks, so.
This is a paradox that, though I have not experienced it much myself, I have heard a lot about.
For reasons unknown, a number of girls here seem to want a 'manly' man not in the sense of outwards appearance but inner traits, which are those you defined as 'motherly', which is perfectly fine, but then end up choosing some muscular jerk and complain about him being unsensitive etc. afterwards. :/
It's not a majority that does that, of course, but still...
Of course, society contributes to that by perpetuating the image of the muscular, yet sensitive, caring etc. manly man, which in reality doesn't exist as much as some people like to believe.