Will you be sad after breaking up? Why are some people not sad?

I think I will be sad after breaking up, but the degree of sadness will vary according to the reasons for breaking up. If in this relationship, I really gave 100% sincerity to that person, but that person didn't know how to cherish or even trample on it, and even found out that she had two feet on both sides, and finally found out that that person was a scum, I think I should feel lucky to break up with such a person, because he didn't deserve my sincerity, but fortunately broke up early. Sadness is for sure. I feel sorry for myself, not for him. I think I will be more sad if I have to part because of the distance.

Some people are not sad for many reasons. Because in this era, there are many people in a relationship, and he didn't give him 100% sincerity, in other words, just for fun. Of course, it won't be sad to break up without sincere efforts. In my opinion, anyone who has paid a little sincerity will be a little sad after breaking up. Maybe some people are good at pretending to be strong. If you don't want to be seen by others, they will pretend not to be sad. In fact, we have no way to identify other people's sadness.