If after eight months Fred Armisen was unable to pull Elizabeth away from Scientology, and Elizabeth was unable to draw Fred in, then there wasn't any hope of this marriage working.
No big deal in Hollywood, eight months is like a typical five-year marriage for us regular folks. What is a big deal is that Elizabeth is a Scientologist and Fred is not, and there have been reports that this was a the crux of their split. Us Weekly reported, "Her religion was as important to her as their marriage, if not more. He could not get with it."
A little background here: I covered Scientology extensively for close to two years; in fact, that's how I met Andrew Morton. When Andrew's unauthorized biography on Tom Cruise came out in 2008, it was EXPLOSIVE and created a firestorm of media attention. Until Morton's book outed Tom Cruise for being second in command of Scientology, they'd managed to keep a relatively low profile. But their usual handling of critics by silencing them through their aggressive litigation and hiding behind "religious persecution" didn't work on the Internet. Throw in the Internet group Anonymous and their incessant hammering, it was clear Scientology's halcyon days were over.
Many ex-Scientologists and critics consider the group a money-making cult and it would take hours to give the kind of detail necessary to understand the complex nature of how Scientology works their elaborate Ponzi scheme, but much more interesting is how their "disconnection" policy has destroyed more than one Hollywood marriage (and plenty of non-Hollywood marriages too.) Based on what I know about Scientology, it would seem very apparent that this may have played a direct role in Armisen and Moss's dissolution.
Disconnection is a process by which a member of Scientology systemically cuts off anyone, including close family, who does not accept or wholeheartedly support the beliefs and tenets of Scientology. This policy is at the core of how Scientology controls its members and keeps them entrenched in their insular world.
While I we can only speculate as to what might have happened, it's not a stretch to assume Scientology had a major role in their split. It was certainly at the center of Tom Cruise's split from Nicole Kidman and his later split with Penelope Cruz (whose father intervened once he found out about Scientology's nefarious methods). The stakes are high in Scientology, which adopts a very strong policy of: if you aren't with us, you're against us. If after eight months Fred Armisen was unable to pull Elizabeth away from Scientology, and Elizabeth was unable to draw Fred in, then there wasn't any hope of this marriage working.
In fact, there isn't one marriage between a Scientologist and non-Scientologist in existence. I challenge the Church of Scientology to prove otherwise, that's how sure I am of their strangle-like hold on members - hence why sites like this exist. But no need to cry tears for Fred, he really dodged a bullet on this one, and plus, he's now free to date hotties like co-star Abby Elliot.