my fp is my ex and i hate it

he broke up with me for a lot of various of reasons but i hate that i basically led to the break up, and then i begged for him back but turns out he was already with someone else.

now when he texts me, i get this horrible feeling of radioactive jealousy when he mentions their partner. i literally break down with him even more and my feelings are so amplified. i cant help it and i hate how im so emotional about it. how can i fix this i hate this so much