I have few questions for you. First, is it the only way you know to earn more? Are you willing to put the money that you have at risk? What if you lose? Do you have other options? If you could answer all questions with yes then you could it's just fine to gamble your wedding funds.
If I will be in your situation, I won't put that 0.04 Btc at risk but I would rather find ways to earn just to sustain my wedding expenses.
Am currently participating in a signature campaign though my take home is 0.003BTC base on my rank. I don't want to lose the one I have now and my other option is to take loan but my rank as a collateral will not be enough requirement for me to demand for such amount of loan.
Thanks for your concern though.
Instead of asking loan here you can also even ask it from your friends or relatives , as you are in signature campaign you can pay them according to it. I dont think that they wont help you. Because as everyone knows it the winning chances are only 1 % but loosing chances are 99%. If you any knowledge about gambling then you can try but think that if you loose this amount also then what will happen to your future plans. So be wise and do anything as it is the matter of life for you as it depends the future of you and your going to be married life.