This is a war. You may think this is a "relationship", but it's a war.
I never would have believed this had it not been for one particular relationship that I pursued passively because I wasn't 100% interested in the girl at the beginning like she had been in me (she was Asian/Filipino, which I've never been all that into but both her body and personality were very appealing to me). It was truly illuminating to be in the position of power for once; everything I used to do to or for women I was smitten-ly pursuing was what she now was doing to and for me.
Since I wasn't too concerned with hurting her or losing her (I was so busy that I wouldn't have had time to give it much thought), I inadvertently had an aloof but cocky and funny frame, and with it I was able to "experiment" with her. As bad as that sounds, it wasn't cruel experimentation at all. On the contrary, I manipulated her and orchestrated situations to be give her a range of emotions, most of them positive with some Dread Game thrown in (before I even knew about Dread Game) to balance out the good with the bad.
After about 5 months, this had become the most successful relationship I'd ever had. To put it crudely, this girl was eating out of the palm of my hand, and she now would bend over backwards to please me, both inside and outside the bedroom--she even started swallowing for me, though she hated it. She became so feminine, and due to this I found myself growing fonder and fonder of her.
However, not long after that, I was starting to become more attracted to her (a girl's femininity will do that to you in time) and began developing genuine romantic feelings for her. I was turning beta, opening up too much about my real feelings and problems, and other little things. The tables had turned, somewhat at least, and she sensed this. She started becoming distant, and suddenly I found myself pursuing her rather than the other way around.
We wound up breaking up probably a couple of weeks later. I could sense that she wanted to end things but she was too decent to do it and because I hadn't done anything really wrong to justify it. I was accustomed to her now and didn't really want to lose her, but I also didn't want to hold her against her will if she wasn't attracted to me anymore--she had been extremely good to me, after all. So I made it easier for her, and we had a heart-to-heart, tear-filled conversation in which we ended things and I told her it was okay to go. We had sex one last time, and she left. And while I missed her, it was a huge weight off my chest because trying to repair a relationship is exhausting, and it taught me that sometimes it's best to just cut your losses and move on.
Anyway, maybe calling relationships a "war" is too harsh of a word. But a successful one does require war-like strategy on the man's part. And you "lose " the moment you start caring too much.