To what point do restrictions such as that of not eating from a dish that my wife ate from apply? First of all, many times she tastes the food in the pot while in my sight. Is the entire dinner then forbidden to me?

Also, if in fact she accidentally partakes of a large expensive dish in a restaurant (or at home for that matter) and decides she doesn't like it, do we then have to throw out the dish thus violating baal tashchit of both money and food?

Your kind response is greatly appreciated.