Shit just got real! I was not expecting that
Seriously! I wondered if it was going to slip away (he'd been "seeing" with less foofurrah and fewer shenanigans) and be less and less of an issue, but I was also thinking it wasn't fair--this was so much more real for Juliet right now, and so much harder to wriggle out of. OR it was going to be a series-ending thing, as the premise was exposed, and whether or not he continued working for the Police Department, "psych" could not still be defined the way it's been within the show (as their company name, f'rinstance) and so it would be a new phase for them all.
I do think it's weird how she discovered him, and I wonder if there had been any suspicion on her part from beforehand. But then again, she's so sincere and nice and straightforward--she doesn't strike me as the sort of person who wouldn't bring it to light, and it's not like we see her having family or non-Shawn friends in whom she could express her niggling doubts.
The three of them acted the fuck out of it, and the look of sadness on Gus' face as he worked out what must have gone down (I'm assuming he couldn't overhear from his phone call, nor would he intend to). For me, third party reaction is a big bit of a story, and they stepped up to this nicely by having Shawn unearth and try and handle issues with their friendship more maturely with regards to Rachel¹ (She's not mentioned in his Wikipedia page. That should be remedied. By someone not me, since lazy).
¹: Lucky wench, getting to snog Dule Hill and Misha Collins. Living the dream, girl, living the dream, I say, ignoring the actual acting she has performed to get roles because let's be clear about my priorities