On this page, you will find information on how to put your wife to sleep using sleeping pills in Twelve Minutes.
You'll find sleeping pills in the bathroom, in the closet next to the door. Using them is a bit more problematic. The most effective method is to take both cups from the apartment immediately after the start of the loop. The wife will want to drink while reading the book - if she does not have her own cup, she will use yours.
Then pour the water into the cup. You can do this in the kitchen sink or the bathroom. Then put the pills inside. - you have to do it out of sight of your wife (for example, in the bathroom with the door closed). You can do all of these things by using the inventory panel on the top screen and dragging items over each other.
Now give your wife a cup with water and pills on the table next to the couch. You have to do it quickly. If the wife asks where all the glasses go, it will be too late, and she will not drink from the cup.