Don’t do it.

If you don’t know what he is going to use the money for and you are not sure about your relationship, don’t do it.

You didn’t say the value of your home. If he leaves only 5% equity in the home, you may still owe money to the bank if he walks away and your home is foreclosed. The typical selling cost of home if 7% of the sales price. With the housing market cooling down rapidly, your home may not be able to hold its value in the next several years. It will ruin your credit if the home has to be foreclosed eventually.

Find an excuse and do the right thing to protect yourself. Try your best but prepare for the worst.