Is it mostly women who enjoy K-drama?

I would say mostly women as men find plots to be too romantic or they don't like that the drama is series (limited patience :))
As for my non-Asian household
Myself... I love k-dramas and will watch them over and over again! ... tears and laughter are good for you as I say..plus I am a super cool romantic with a heart of gold and a room for imagination in daily life :)
My mom, likes them and will watch them from time to time, but prefers something else as a senior has a hard time following subtitles.
My dad, thanks to me loved City Hunter and will watch action dramas although he will watch other k-dramas from time to time if mom and i would ask company: ... which makes my dad that much more wonderful by the way!
My husband says it is too long saying: it's not his cup of coffee. He simply is not into dramas but does not mind if I watch them myself, or falls asleep on them, borrowing me his awesome shoulder to cry or laugh on :) 
Our teen son says ... OMG mom... another drama!!!! ::::???? and gives me a rolling eye or just runs out of the room without even saying anything :)  LOL
Our cat "Pilot" just sleeps next to me sometimes or can care less what's going on around anyway...
Still, no matter how things are around here, K-dramas are present in our lives even if we want them or not LOL and that is ALL THANKS TO ME :) :)

I'm watching because of romance mostly. But in no way limited to Korean dramas.

I think most men wouldn't be that different to women in this regard.
But there's a stigma. At least that's how I experienced it. Role models for guys, being what society defines as "masculine" doesn't go very well with romance, especially when it's considered to be a feminine domain and even if you don't care about such things, it's less likely to happen.

I didn't consciously avoid anything with romance, but there weren't many opportunities since I didn't expect to like it. (action, horror,... = exciting, romance = boring)

It came as a very, very late surprise to me, when I recognized how much I was into love stories.
I think that's only natural though, otherwise we'd be totally retarded by design when it comes to feelings. And that to be a biological factor seems crazy to me.
Sure, romantic dramas are mostly from the females' point of view, but I find that very refreshing :)

Martin, I think it's out of question that women watch it more, just look at the users on MDL, even if not significant for the world population, another indication is the fanservice for women you'll find in most romantic dramas. But at the same time I strongly believe that society, environment, upbringing... "nurture" is to blame for this huge difference for the most part.

@JayRandom I like that you mentioned "(yes, even men can tell when other men are hot)". I think it's incredibly silly whenever men point out how they can't possibly tell. Being afraid of being called gay or what. Really so stupid hahaha
Hmmm... I think what you mention though, those reverse-harems aren't 90% of dramas, or am I really mistaken (still a newbie).
Let's take My Love From The Stars for example... or My GF is a Gumiho, or Sapuri or Ohitorisama, yes there might be one competitor, but this doesn't bother me at all. What I can't stand are these overly aggressive, arrogant males.

Bottom line for me is that I really enjoy romantic dramas originally made for women.

I agree Martin.
I think that it's especially noteworthy how homophobic straight men in most (not all it seems) western countries are.
Not only is it stupid to jump to conclusions just because something concerning you might be outside the norm, but the reaction and fear is even more ridiculous, as if being gay was something terrible, something to be afraid of :D
But that's quite offtopic now.

BTW: I envy that man's body in your picture. I'd give a lot to look like that.