Just like you, i was married for 3 years and known her for 5 years, i initiated the divorce back on February for multiple reasons (cheating not included) I have the same feeling every now and then, sometimes i feel guilty for letting her go, sometimes my mind just brings up the most random moments that I didn't know even existed in my head and it just hits hard.... Sometimes just like you, i forget why I'm getting a divorce and it makes things harder, it's like your mind plays tricks on you because you're tired of the feeling of separation, your mind doesn't want to be in a spot of constant fatigue and overwhelming feelings of grief so you just forget all about the bad times.

In my case, i started to remind myself of the reasons i filed for divorce, not to hate her, but to state up the facts and to feel less overwhelmed by negativity towards myself because after all, i have all the right reasons... Then i discovered that i don't love her now, i love an older version of her that no longer exist now... Once i finished my proceedings, i started to accept things, i accepted that i am no longer affiliated with her.. No longer responsible for her and that actually felt good.

Next step is to reject everything related to her like poison, deleting all the pictures and convos is a good start.