Here's why you'd better not have a cash bar at your wedding. Your guests are spending a damn fortune to be there for you —  don't squeeze $5 out of them if they want a glass of wine.

American Express just released the results of their annual study on the cost of weddings; and in 2015, you'll spend an average of $673 to go to one. That's up 14 percent from last year and almost double from 2012.

That cost is spread across airfare, hotel, food, a gift and clothes.

The study also found 43 percent of people have decided not to go to a wedding for financial reasons; and 36 percent have taken on debt to go to one.