Oh, David, this could be a long, long, long post. Possibly a book! But I don't have time for that right now (so y'all can breathe a sigh of relief).
Let's start simple. What does Mars represent? Severence, cutting, separation, war. It creates strife. It tears people apart.
And that isn't sex.
Venus, on the other hand, is the planet of conciliation. The one that brings people together. The one that makes us DESIRE. The one that celebrates art, and beauty, and love, and connection on a deep, deep level.
And that is about sex.
There is so very much historical stuff here that I could go into (that's the book part), and astrologers wrote about it in the past. A lot. So did philosophers and poets. It was kind of a big deal. A huge deal, for most of us, and even though we have more technology now than we did then? People - we're still pretty much people. That hasn't changed.
Mars can inflame, if you combine it with Venus, it can create a lot more lust, but it's lust, it's not sex. (Another book can be added here.) But it isn't necessary. It's really not. That creative impulse - it comes from the sun, not from Mars.
I think the reason I've been despairing so much reading this thread is that it makes me think people think that nobody had sex, or at least meaningful, or passionate, or perverted, or wild, or wonderful, or intense sex or relationships before - Hugh Hefner discovered sex? Or that if they did, they had no idea why (yes, they did, it's a big topic in the literature) until the outer planets came along.
And that's just wrong.
Cheers, mate.