How do i stop caring about someone who I know doesn't care about me at all ?

This is such a difficult situation to get out of but it isn’t easy to just stop caring about someone as this is human nature. The fact that this person doesn’t care about you shouldn’t mean you should give up on them, you shouldn’t be in the mindset that you must receive fondness that you give. I personally still care about alot of people in my life that no longer care about me but I wouldn’t wish it away because it shows my human side. It’s okay to care about someone but don’t obsess over them and get upset over their like of caring! You are the better person and they may not have time in their lives to fit you in so don’t feel bitterness towards them