He Always Remembers To Forget
When our parents start to forget some things that they do, it is one of the clear signs that they really are starting to grow old. Things like holding the remote and forgetting where is it, or wearing their glasses and starts looking for it because they thought they lost it. These are the things we can easily forgive as it is inevitable due to their age.
However, this father is unforgivable because even though he sometimes forgets to delete his browser history, he never forgets to put divorced or widowed in his multiple dating profiles. On top of this, his kids would also notice him sneaking out to meet someone. Now, that is the forgetfulness that you cannot forgive.