Can anyone explain this I am so confused?

I had a 9 month relationship with my ex.. and after we broke up the communication was totally off altho we used to be friends before dating.. i moved on an within 3 months exactly i met this new guy we started hanging out and we decided to date i fell hard for him and he was much more better than my ex in everything.. more caring and he even thinking of us moving the relation to something more serious i am feeling happy and so secure around him and got feelings i ve never exprienced before.. Yet , whenever i space out and start thinking, my ex comes into my head and there is a flashback to memories with him. altho there is no raison i litteraly don't love him at all and we didn't even talk nor nothing and when i am on my own i keep saying his name out of nowhere.. i don't know why the heck this is happening while whenver i try to play a memory with my new boyfriend its all a blur.. i love my boyfriend a lot but why this is happening to me
Can anyone explain this I am so confused?
Post Opinion