Guy here, and I enjoy romance if it's done right. But 9/10 times it's a shoe-horned in relationship just to have a bit of love to spice things up. Romance is about the dance of courtship, and when you look at the top romance stories that have endured over the centuries, very few even mention sex or the desire of such as any motive for why the characters are attracted to one another. I'd also say that the most intimate moments are those which don't involve sex, because that's when you're going out of your way to make someone feel good for no reason other than the fact that you love them.
As for ancient people being more prude, that is indeed a modern misconception. There are many stories about promiscuous Gods from the old world. And it didn't just stop at sex. I think there's an old norse tale where it's suggested that a river was formed because a female giant parted her legs and urinated. But at the end of the day sex is sex. It's been cool since the dawn of existence because nature would have failed miserably if the means in which any species reproduces is so unpleasant that they avoid doing it.
I fall into the crowd who gets uncomfortable when reading sex scenes. But that's because most are weird and awkward. You see them coming from a mile away because the attraction is so forced and corny--whenever two characters cannot get together for whatever reason they're
going to get together--and it often ends with that seemingly mandatory and equally terrible simile for the orgasm. In most cases I suspect the author is merely living their own fantasy through their writing. That's cool and all, but that's what the erotica genre's for. If I wanted to enjoy some porn I can find far better avenues of getting it than through books.
There's actually a large thread on fight scenes further down this forum.
http://fantasy-faction.com/forum/writers-corner/fight-scenes/ . It might be worth giving it a browse because the principles most concluded with there are the same ones I'd suggest applying to sex scenes. Readers don't need to see every thrust, swing, and miss. And the scene should never be longer to read than it takes to do--which, contrary to popular belief, isn't the 10-30 minute sessions people like to imagine, because then they either aren't really attracted to one another, are under a lot of stress and not in the mood, or else have been getting themselves off with their own hand at regular intervals leading into the event.
On a final note, here's some food for thought. Think of one of your close friends. Now imagine that you walk in on them while they're having sex with a partner who they love dearly and are very intimate with. How would you react and feel? Even if you'd smile and laugh about it later, would you pull up a seat and watch them finish? Because that's exactly what you're making your reader do when you go into the gory detail of such moments with characters who they've gotten to know well and hopefully have an interest in.