I vote for two cats in your house as well. My first cat was not having problems with being home alone, but I did notice that he enjoyed having a companion.

In fact, we are on our third "second cat" (two others are at the Rainbow Bridge). By chance all of the second cats were kittens. But I would not hesitate to try with an adult cat.

Besides, you'll get double the laughs and love if you have two! Best wishes!