I'm pretty sure it's implied that the shadow children Melisandre uses to kill Renly (and ... some other dude at Storm's End?) were the product of some kind of sexual act with Stannis. I was still a little annoyed by how quickly she was able to convince him to do it, though. It's Stannis! Come on!

As much as I love Petyr, I think he's suffering from the dumbing-down the writers are giving the entire show. I liked the idea of his little clash with Cersei in the first episode, but having him basically outright say that he thinks she's sleeping with her brother - in front of other people, no less - is just ... not Petyr.

And, lol. Totally Denethor, Boromir, and Faramir. Can't unsee.