Short Sale or Deed in Lieu

We bought our house 5 years ago with a 3 year plan to move. Obviously the market tanked during that time so then our house was completely upside down. I am not the type to walk away from something so I continue to pay my mortgage, never have missed a payment and never intend to. I feel a sense of obligation to stay because I agreed to buy the house, but on the other hand we knew it was a short term house for us, so now our needs have changed. But in order for me to sell my house I have to come up with 100k, which I do not have. We are pretty content with our house, it isn't much, but we knew as the kids get older we would want to be in a different place because we are on a highway. And the older they get the more they are active and in the future driving etc, and no way in hell I am going to let them try to learn to drive from our current house. So, owing more than my house is worth, what are my options here? Hate to ask this question, but any credit score or lending professionals on here that can shed some light on how either of these will affect credit and ability to buy in the future. Any other options? I ask because I probably don't have any other options at this point.