When you are with someone for a long time, and when you have met them when you are young, you grow around each other and bend and twist as you intertwine mentally and emotionally.
When you lose that person catastrophically then you must necessarily be willing to reform to match another.
Why and What does this mean for us who are widowed? It means that it is unreasonable to seek an exact copy of your previous partner as a plug compatible replacement of such a person exists in a diminishing probability according to time you were together. Humans are not manufactured artefacts or clones.
You need to identify what are criteria that you want to keep, and what you will discard.
You have to be willing to be reshaped by another’s needs and wants as you reform.