Get your pointy stick out; I'm afraid you're going to have to burst that bubble. You can do it gently, however; I think the key is to tell her that you want to save money for the family that you want to start, as well as some of life's finer things down the line (like, I dunno, a house and maybe some food once in a while). If you spend lots of money on one day's celebration, the rest of your life is going to be an uphill struggle of scrimping.....
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There are also lots of ways to be frugal yet romantic on your wedding day. Plumb your resources; know anyone who lives on a lake, so you can have an outdoor wedding? Shop craigslist and ebay and consignment stores for wedding dresses. Perhaps you have friends or family who can pitch in to create flower arrangements or cook the reception dinner. Or do a slew of fancy appetizers instead of a big sit-down roast-beef buffet. That'd would be classy and very romantic. Think outside the box, or in this case the wallet. Good luck, and congrats!..

Gently remind her that ... it's one day and altho ur (together) budget may not afford her the extravagent wedding day she initially dreamt of ... u promise that u'll do everything u can to make the marriage for every day after that..... more than she'd ever dream ......
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This is a great exercise to go thru together, setting up a budget, determining what's important to both of you, negotiating so get the most for ur money, making concessions, deciding what luxuries have to be eliminated ... a whole sleu of life lessons ... that u both will likely need to get used to dealing with ... once ur married...
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So be nice, but direct and honest "Honey, I love you to death, but if we do ALL of this, we'll be starting off our new life together ... drowning in debt...Wouldn't it be better to cut back on some of the luxuries & know that we'll have enough money ... so we can spend the next year living like we're on our honeymoon ... instead of spending it trying to get out of the hole from one day?"..

Hmmmmmm, you should try to let your partner know that the best planned weddings are not elaborate but carefully executed.It is better to plan and satisfy all your guest than having a crowd and not satisfying them,so plan to your pockets size and God will help you.Try to avoid debts and you will live to enjoy your wife.Visit my blog to keep your self updated about marital life.www.maritalroundtable.blogspot.com..

The only thing you really can do is sit her down and explain that if you follow through with all her gorgeous, but elaborate plans, you will be worrying about your debts forever...

Just straight out tell her what the budget is. Maybe she has some cash sacked away that you don't know about. Or maybe she would be willing to take another job to earn the cash. Or get a sponsor for her wedding -- I have read about companies who are willing to make donations if you put up a little sign and a note in the program. A lot of people do go hard core into debt for a wedding. But there are budget wedding magazines and web sites you can show her. She can do a lot of the flowers herself, or scale back on things like the dress. If you cannot communicate about budgets for the wedding, how will you talk about these things in the marriage?..