And this news should be nothing new to you. Stop complaining and accept him for the person he is, because he obviously didn't bother you with his childlike behavior before the engagement.

While not a personal fan of Batman or Star Wars, I don't particularly thing OPs fiance's interests are childish. There's nothing wrong with doing that kind of thing. I mean - well - growing old is mandatory...but growing up is optional :p

Not the wedding cake he deserved, but the wedding cake he needed

not for me but if it makes you happy then geek out if not then go find a grown up man to be with

hmmm well u dated and "know" the guy so u know what ur getting into. tell him be grown up for once, stfu and on ur wedding anniversary yall will get the batman cake. or better yet when his birthday rolls around give him the star wars theme and the batman cake. not at a wedding.

no your marrying a nerd

Find a compromise, because it sounds like you are rolling over and giving in to all of his demands. You only get one wedding (hopefully) and it should be enjoyable for you both.

Throw in a little LOTR while your at it.

your a moron, you have no morals

Do nothing as a geek He is He will understeand better than anyone that : The cake is a lie