Am I being a b@#$% or no?

My fiance and I have been planning our wedding since last January. We agreed on a big church wedding since we are both Catholic and reception because we have big families. Now that we are in the actual planning stages he wants nothing to do with it! And he has been writing a book he thinks will make him famous, which is great. BUT he wants to spend 1300$ to publish this book instead of contributing to our wedding fund. I am so mad I can't even talk to him right now! Am I over reacting or no?