Smash/WMG

Karen's boyfriend is really a British spy, and the show shares a universe with Spooks

 * Which would make Karen's boyfriend's real name Zaf, and his employer Adam Carter and whoever he answered to in MI 6, which would make the show set in 2003 or earlier, so as not to interfere w/ the canon of Spooks. Think about it, he seems very interested in dating a waitress who happens to be an understudy in a random play about Marilyn Monroe. What if he's investigating it for ties to terrorism? He also looks EXACTLY like Zaf, almost as if they share the same actor.

And then there's the real reason why he won't be on next year, which is because he's been recalled to Britain to join MI-5 with Adam.

Ivy will eventually die due to drug overdose and pressure.

 * Isn't it kind of obvious?