The 'Fringe' actor admitted that an allergic reaction kicked off an evening which went from bad to worse.
He told UsMagazine.com: ''Our first date was a miserable one. I took her to an Italian restaurant, and there was some flower that was blooming. She was allergic to it so she sniffled and sneezed the entire time.''
The 34-year-old star continued: ''And when I get nervous, you might have noticed I talk a lot. So I just chewed her ear off for an hour and a half. It was amazing. I'm surprised she ever called back.''
Together since 2006, Joshua and once-married Diane, 36, are now thinking of starting a family.
He said: ''I mean, I'm at that age.''
However for now, he is focused on wrapping up the fifth and final season of 'Fringe'.
He said: ''The focus right now is to just make sure that all the things we were paying lip service to we actually believe. We really want to have the opportunity to kick ass this last year, so that we can honour the dedication and the commitment people have put into it, and also our own commitment to the show.
He added: ''Since we were given this pretty rare opportunity to finish up on our own terms, we want to make sure those terms are good.''