Extreme obesity

When do you lose mobility?

How do I avoid immobility? At what point does a person lose mobility? How do those people do to stay active with 600lbs?

I have + 500lbs.
I like to be fat, I love the food and comfort of my sofa and I hate doing any physical effort.
I never stopped getting fat and fattening becomes easier.
My husband tries to talk about this and tell me that he will take care of me, but he introduced me to the fetish and I guess he will keep encouraging me to get fat.
I'm afraid of immobility, I do not want to live in a bed, but I feel like I'm going that way.
6 years