You become a fixture in the room, like furniture
Eventually you fade from conscious perception, like a coat rack or a painting on the wall. People no longer greet you when they come through the room, or talk to you when they sit down to watch TV.
When they bring dates home, they will often sit on either side of you and make out with one another. That's how imperceptible your presence has become.
You die of sepsis and malnutrition during an episode of Bad Grammar Kids. They have to bury you with the couch, which has become like another part of your body.