Perhaps Connie didn't get disciplined because Jack's boinking her, too.
I seriously doubt it. Connie's too young for Jack (and besides, if that were to have happened, it would have during season 17 in all likelyhood, before Linus Roache essentially replaced Fred Thompson in the cast). Now, if it were Sonya Paxton (played in four "SVU" episodes by Christine Lahti), I could see that given Sonya is probably very close to Jack's age.
Anyway, this episode had in a lot of ways a very sad finish to it. As others have noted, it also (again!) blows away anything "SVU" has done in recent seasons (it would be interesting to see Mariska do another crossover, perhaps as suggested with Olivia working with Bernard on a cause). The moral dilemmas in this episode were quite interesting, and in all honesty, I could not see Connie being fired for what she did, mainly because she seemed genuinely concerned about a potential Brady violation (remember when Casey Novak, played by Diane Neal on "SVU" from 2003-'08 commited one and wound up disbarred?). Whether it was relevant or not, if it had turned out they didn't divulge the info Connie gave them and they found out on their own after he was found guilty, perhaps the defense attorney might very well have tried to go for severe sanctions.
One other thing that came out of this to me is that it's now clear that Connie and Michael are clearly NOT a couple, and probably never have been: Connie's wanting to transfer to White Collar after what happened, but Jack denying it I suspect sets up for even more tension (and I suspect they may have done that as well in case Dick Wolf decides later this season to have either ADLG or LR (or both) pull double duty and have their character(s) cross over to "SVU" to finish the season in the ADA's slot on that show after Stephanie March's current run on "SVU" ends following the 14th episode).