Spouse is dead and children are adults but I'm still getting child support notices do I still have to pay?

You still owe the money to her estate. The kids still had to be paid for when they were growing up. You deprived the kids of the benefit of that money as they were growing up. The estate that the dead spouse left is poorer by the amount you didn't pay. You violated the court order. Courts don't take kindly to being ignored.