What is it with the mixing of sexual passion and violence?

I posit the following:
I think that men have an instinct to hurt their lover, physically, during sex, because it is a hold-over from our animal instincts.
By copulating forcefully enough, a male can assure that the female will be too hurt to copulate with another male. This makes his sperm the last ones in, and the more likely to actually fertilize the egg.

Monkeys use the technique of trying to be the last to ejaculate. They cue in line, and as soon as they ejaculate, they get back in line. The last to ejaculate is most likely to be the father! So the quicker he ejaculates, the quicker he can get back in line! Poor little female monkeys, right??? I can hear some woman thinking to herself, “So it wasn’t a man I was sleeping with, it was really a monkey!” Now now!

Ok, why am I even thinking about this? Well, I hate to be the one to tell everyone, but I have come to the conclusion that men have an instinct that is violent in sex. Some are more in touch with it than others… and of course it is more a symbolic expression than real, unless some mental illness prevails. But still, I can’t help but be aware that sex has this element to it… the “Fuck Me Baby Effect”. But why? What purpose, in terms of animal evolution, could it serve? I think I denied it when I was younger. The older I get, and the more honest I am about my sexuality, the more I realize this. And in talking to other Men, I think I spot it in them too. If you are a “nice guy” and you are fairly self-observant, you can’t help but feel this passionate, wild, driving force when you are with a woman. Yes, while you are consumating the most intimate and tender and spiritual aspects of your Union… maybe with someone you would rather die for than see harmed… it is such dichotomy. And no one talks about it, except maybe the BDSM folks; and they are probably adding another dimension to it.
So is a woman, when she submits to a man’s vigorous thrusting, essentialling saying, “You are the One” ; “I want to bear your children” ; “Take me, I am yours” Reminds me of the finality of mutual suicide, when 2 people ensure that they will be each other’s last mortal experience. I hope I’m not creeping you out with this? It is curiosity here, not some fetish of mine.
To prove that sex is intertwined with violence, consider this:
Both men and women are capable of climaxing without anything rigorous or even that physically strenuous. How does that sound to you? Kinda boring, huh? See my point?
I’ve been wanting to write about this for a while, and couldn’t find the right time. I’m not at my “writing best” at the moment, so I might revise this sometime when I’m feeling more articulate. I invite your comments and ideas.