the high school aged (?) guy has a habit of counting to ten (?) seconds before making any decision and he ends up having to move away and before he can tell the love interest his dad unknowingly tells him so there’s a confession type scene but his counting habit messes it up or something and then there’s a time skip to when they meet as adults or college aged ??
I remember the main guy (habit boy)’s dad had a lover and the reason they moved was so he could be near the grave of a past lover ?? Any help would be great !!

It's probably Me wo Tojite 3-Byou by Aniya Yuiji.