Donna I am so sorry too hear this. Thank god that Otto is doing well.
ALL mine (26) are indoor only.
When 1 is adopted I tell them that if I even think that they are letting them out I WILL reposes that cat and find a new home that is more responible.
I have several that I was told that they DO NOT do well if kept inside.
I am here to say that it is wrong. One renamed Henry I was told that he will try and get out no matter what.
He new station is on top of the fridge or the upstairs front window and has not made any attempt to GET OUT. I have 5 ferals in house. Again no problem, they seem very happy.