I'm not going to say I tried to stop them, but my characters having sex was not my idea. I blame it on the plot.
Because the *thriller* is following an exact time line, counting down to the explosive (let me tell you) ending, there have been, as the end draws closer, chapters of the good guys offsetting chapters of the bad guys. Eventually, they both had supper at the same time. Then they both retired for the next-to-final evening at the same time. (Trust me, no on is sleeping the last evening.)
Sooo - wouldn't you know it, out of all these characters, a couple just decided to break their discipline and have sex. And then, in the alternating chapter, another couple decided to, er, repeat an earlier engagement. Let's face it, if the author doesn't describe what is going on, he is no better than a voyeur.
However, an aspect of the thriller is, though the violence can be as graphic as all get out, the sex should not be pornographic. The general thriller readership is not after *that sort* of thing. Plus, you don't want to deflect your reader's interest too much. And - anyway - pornography becomes tedious quickly.
So, though the bad guys get more action than the good guys (it was their idea), there are details not, er, detailed. The good guys get to do it behind closed doors. After all, I have the sensitivities of Louie-the-dog to consider.