I've eaten expired peanut butter a lot before and it's never caused any health issues and I never got sick from it.
The worse thing that could happen is you get an upset stomach from eating expired peanut butter but even when peanut butter is expired it's still safe to eat as long as it has no mold on it or doesn't smell bad.
The expired peanut butter may have changed texture and may not be as smooth or creamy as before when it was fresh but the expired peanut butter is safe to eat.
There's no need to throw the expired peanut butter out if it's expired and you can even used the expired peanut butter to make peanut butter cookies with where you won't notice a change in the texture or taste.
But I eat expired peanut butter all the time and it's been perfectly fine and even my kids eat some expired peanut butter and nothing is wrong with that as they never gotten sick from it.
If the peanut butter smelled bad or had mold then I would throw it out but otherwise I would eat it without even worrying about it.