I agree with most what has been said and think this stuff will always evoke memories and sadness. Even those who have reconciled would probably still have some sadness if they thought about it in certain ways.
I think the other thing is that when you truly let go (or each time you let go a bit more) you need to remember that part has its own grief cycle, by not getting go to an extent you've been in denial and so now you have you need to work through the stages. Its natural and normal and healthy but still feels like [censored].
Personally I thinks that's why WAS do what they do, take a band aid approach, just rip it off then anesthetise the pain somehow.
As your signature says - all will be well
Both mid 30s, 2 young kids BD 7sep14 XW moved on long ago, now living with OM1 D paperwork in progress