My ex boyfriend and I moved into a house ~ 3years ago. We both contributed to household expenses equally. He is on the mortgage, I am only on the deed.

I moved out in Oct.. 2007. I just received a letter from him stating that Countrywide loans have reaccessed the second mortgage and have suspended any further draws on that account. I suspect he has increased the original amount. They also state due to the decline in the housing market , the original accessed value is significantly lower.

He has sent me a letter stating there is zero equity left in the house and should I sign a quick claim deed or I will be responsible for half of the whatever amount was not covered in the sale of the house.

Would I be responsible?

If you are not a signer on the mortgages then you have no responsibility for the debt. However, you have to weigh what you put into the house at purchase and during your occupancy. You have to verify his statements about the value of the house vs the equity. If he's right, then I would quit claim the house to him to make sure you have no entanglements.