This question comes up quite often. You may have many different options but your ethical obligation is to follow through on the contract you made with your lender, which was to make payments until you pay it off or pay off the lender in full. Asking the bank to take a short sale in this situation is simply deciding to cheat them & society as a whole. It's just not right.
Beyond the ethical issues, you will hurt your credit for years to come, which could lead to higher rates on other loans and credit cards. Plus, you really need to speak to a tax advisor regarding how the tax credit works in your situation.
Congratulations on your upcoming marriage, but at the same time do the right thing and own up to your financial obligations.