Should I let my 21 year old son and his 19 year old girlfriend live in my house for free? They both do nothing around the house.?

No, how is that being a responsible parent? They help create the utility bills - they should help pay the utility bills. They eat the food you buy - they should help pay for the food you buy.

No they are adults and need to pay their way.

NO WAY.

Nope. Two adults. No reason in the world that they need live for free in a household you pay the expenses for. Two legal adults. Being kept children isn't going to be doing them a favor.

HELL NO. Im sorry but unless you're son achieved something in his life, like going to an ivy league school, creating business, taking care of you, or paying you back for all the years of money spent on him, then there should be no reason to invite someone else who isn't family into the house. He should start caring for himself.

No and it is time to you to sit down with them and have a talk. You are within you rights to ask for some rent and for them to do some chores. Be tough because they need it.