Emma’s dated a few “ogres” remember? So I’m sure since Neal she’s dated some sketchy guys in one way or another. I don’t think the married man she mentioned is Ryan. That was a fake date. She was on the job. She had no emotional investment with that guy. And the way she mentioned it to Mary Margaret, it seems like there was some hurt involved with the married man.
Emma also mentioned she doesn’t go pass a one night stand. But, that’s 28 year old Emma. I don’t think Neal was the last actual relationship Emma had. Probably the last guy she ever loved. But, I’m sure she dated guys, had boyfriends, and they all went to crap for one reason or another. And so within the course of 10 years she ends up being the type of girl to just… be the one night stand type. So I’m sure somewhere along the way, she got involved with a married man. Maybe more than one (at different times). No reason to assume it was Neal.