I need help

I’m having a hard time getting over my ex , one minute I’ll think I’m okay and ready to move on but he will text me saying I miss you and I fall right back in and end up in the same cycle as I was before. I don’t know how to end the cycle for good. I always have in my mind that we will get back together eventually. I think I need to block him but I’m scared if I block him it will be over between us forever. I feel so dumb for this because he has cheated before . Someone please help with personal experiences or any advice !