When I was a teen and Superman II came out, when Superman realized he and Lois were in love, he de-supered himself in the Fortress of Solitude so he could be with Lois. Right after he emerged from the crystal cage that drained his powers, the first thing he does is take Lois' hand and escort her to a conveniently placed bed that we had never seen there before. This implies it was necessary for him to lose his powers so he could have sex with Lois.
The problems involved in this situation are well covered in the wonderful essay by Larry Niven, Man of Steel, Woman of Kleenex.
But I also know that Superman has been in the comics for decades. A friend of mine once said, "Oh, he tells her who he is a lot, but he always makes her forget it again later."
So how have the comic books (since this is Superman's primary medium) handled this? Were there different ways it was handled, or was it always handled the same way? Have they literally kept Superman and Lois from having sex for decades? Or have there been times when they've ended up in bed together? How do they deal with the issues of the Man of Steel having sex with, and not killing, a woman of Kleenex?