Sounds like you are doing very well. Why is he asking you not to hate him, has something else happened?
As for me..
my dd talks about xp all the time. We talk about him, he was a huge part of her life, particularly as she has no contact with her biological father. he was for all intents and purposes her 'dad' iykwim.
She/we have lots of very happy memories. She says she misses him still but not as often.. it depends & varies on environment, moods, triggers etc
I try to encourage the idea that just because we aren't a couple anymore that we are still friends and he reinforces the fact that he still loves her etc when he sees her... it's only ever ad-hoc visits but dd seems happy with that. Always left with a 'see-you soon'.
I find it hard to see them together because they very obviously love each other so much.. I just look at them and feel their pain in an "I did this, I took them away from each other" kind of guilt feeling.
It'll always be hard to not be with someone you feel so much for but it's easy to remember the good bits and the bad bits get all hazy. I often have to remind myself just why we are not together.