I really want that DVD, but how am I going to convince my fiancee (she'll be my wife by that point) to let me buy that!? Yikes!

Surely she knows of your hobbies already? She should be taking you whole, not trying to remove parts like fandom. A good wife will support your passions, including "silly" ones like Aquaman.

It's not the fandom she opposes -- its the expense!

Hmmmm.... That's a tougher one. I'd promise something, personally. Washing dishes, cleaning clothes.

And, depending on her attitude, either make a party of watching them with her, with popcorn! Or making sure she doesn't have to see them at all, if she isn't into it.