I have a bf but i miss my ex?

Ok let me explain

My boyfrjend is the love of my life. I love him so so much and i hate my ex. The thing is i really dislike my ex but i miss the MEMORIES. He keeps popping up in my thoights and i dont understand why because its happening randomly. Idk why but i hate it because it makes me feel like im cheating but i dont even have feelings for him.

Please help me, how do i get rid of him in my thoights?