I have both Pluto and Mars in Scorpio. In relationships of any kind I want depth; and not just penetrating the surface a bit, but instead as deep as I can possibly go. Seems to be the trademark 'all or nothing' of the placement, which in my case at least is true. I want intensity because it's real, those extremes are where the truth is. I want the good, bad, beautiful and ugly of a person, I want to see it all, feel it all, embrace it all. As for possessiveness, my own take on it is that when I'm in a romantic relationship, it's like a fusion for me, and I'm possessive of my space and all that's within it. It's mine, after all, and I claim it, defend it, fight for it. Why is Scorpio love 'dark' to some? I think it's the intensity itself, the exposure. There are no superficialities in love with me, I desire to see and embrace the depths of a person's soul, wholly. And this seems to be transformative to some extent for those I get involved with, as inner truth is inevitably exposed, shadows faced, problems resolved. I think 'love is war' might be a good phrase to keep in mind when thinking about Mars wearing the face of Scorpio.