Unfortunately, lost cats are pretty common; it's all too typical to walk by missing cat posters affixed to a streetlight or bus stop.
There are several reasons why a cat may leave your home and not return, and it is generally not the owner's fault.
They will achieve reproductive age and exhibit behaviors such as attempting to leave the house in search of a mate.
To put it bluntly, your cat could be having an affair with another human. Cats are naturally inquisitive and are drawn into strangers' houses.
Depending on how far a cat's hunting takes them, cats may lose their bearings and become disoriented.
Don't take it personally if your pregnant cat prefers time alone, but be aware that this could be the reason your feline buddy has gone missing.
If you've recently redecorated your home, had a kid, or simply changed your routine, cats will notice, and occasionally fleeing will be their coping technique.
Your cat may simply be getting older and frailer, causing him or her to seek out peace and quiet away from any disruptions.