I think some people really are more able to "choose not to be upset" than others. I relate your issue to mine of obsessing over insignificant things or events. Usually I can stop myself from obsessing over something insignificant but sometimes I can't. It usually works by just putting the event behind me and moving on to what I was doing or need to be doing. Whatever it takes to get it out of my mind. Maybe you just have less of this ability to control what upsets you and how long it affects you and how soon you are able to let it go?
The second example... hmmm it works for some things but it sounds like he went to extremes. But looking at it pragmatically he may have helped her. If he dies first she will no doubt be better able to handle life on her own. I've seen situations where the husband handles everything and then when he dies the wife is stuck not knowing how to do the simplest of things and having to learn while also grieving.