I was a werewolf. I became a vampire in order to enter the Soul Cairn. After doing this, there is the option to become a werewolf again through Aela. I did this in order to be able to work with the Dawnguard again. Later, I became a vampire again through Serana, in order to re-enter the Soul Cairn, and also because it is kind of awesome to be a Vampire Lord. The Dawnguard went back to being a bunch of jerks, so I went to go back to being a werewolf, but the option is no longer available. Aela just offers me two jobs now (both animal extermination). I got cured of vampirism through that guy, what's his name, the dude in Marthal. Still no werewolf option, just two jobs. It may also be of note to mention that I am married to Aela. I'm doing the Animal Extermination quests now hoping the option will magically return, but I have my doubts, so... input? Has anyone else experienced this? Is there any fix?