No I don't think you missed anything. There's a spoiler for this week (or next maybe) that says EJ explains things to Anna so maybe we get more detail then.
We know from Corday's blurbs back before sweeps that a 'longer story arc involving EJ realizing his feelings for Sami' is ahead. I think EJ is conflicted & we're supposed to be wondering what's up not only b/c he brought Syd back rather than leaving town but also b/c the writers have had Anna dropping hints left & right about EJ loving Sami. That's the last thing she said to him when he was leaving w/Syd Friday & then the next we see he's at the pub.
I think at this point - & this is just my thoughts - that EJ still has something planned. I think Sami's reaction to him returning Syd, as well as the family time Sami & EJ & their kids have in coming episodes, serves as a catalyst to EJ realizing he really wouldn't be all that happy even if he managed to take Johnny & Syd away from Sami.