Postpartum sex is a big deal. Sure, you and your partner have had sex before, but there's been a lot going on with your fancy bits of late and none of it has been remotely sexual. So there's often a lot of build-up to that "first time after baby." Anticipation, worry, fear, excitement; chances are you're going to feel it all. I know what it's like to be a new mom in this situation, which is why I had dads describe what sex after baby was like for them. In my opinion, this information is useful... or at the very least sort of interesting.
I'm sure there are as many different answers to this question as there are gentlemen to answer it. I talked to 10 dads (who, out of sensitivity to their partners, mostly wanted to remain anonymous) and there were some common themes but, truly, a variety of different emotions and physical and mental challenges. Another area I saw a lot of variety was time, which proves that postpartum sex doesn't occur on a set timeline. When you have sex (and what kind of sex you have, incidentally, because it's not all about the P in V or anything in the V for that matter) is entirely up to you. When you and your partner are physically and emotionally ready to get back in the proverbial saddle is when postpartum sex is officially on the table.
When you are prepared to take the plunge back to Sexytown (OMG that sounds horrifying, I'm so sorry), here's what you might expect, at least from a male perspective: