A lot of cats, once they get a taste of the outdoors keep wanting to go back out because it's new and exciting.
Others however will be so scared from the experience they never want to go out again.
Keep him indoors, and stay very alert to when people come in and out of the house.
If you have to, when someone comes to the door, or you have a lot of people leaving at one time, put the cat in a room behind a closed door until everyone has left and the doors are closed up.
When you enter or leave your home and the cat comes rushing up to the door, stomp your feet really hard on the floor, and slowly walk towards the cats direction to scare her away from the door way, and then quickly slip outside.
No dog or cat has ever gotten passed me, and I use this method and more when needed.