what is life really?

I broke up with my boyfriend 3 years ago , the relationship didn’t last that long but i really really loved him and i believe he loved me too but the relationship ended because i kissed someone (it cant just be that does something little and sees nothing wrong in it as per you dont have feelings for the person and its just a game) honestly i thought i could get over the breakup but its been really difficult because he said some things that have scarred me for life and i dont want to get into a new relationship
what should i do?