No, not really. But I think that's mainly because I don't develop serious "crushes" for celebrities. Never really have. But still, I adore people for their works... like Terry Pratchett... yes, I feel proper sadness then. Not like a shock, but deep sadness that they are gone. It's not like a personal shock, but a deep regret somebody who gave so much to so many people is no more with us.
I suppose it's because we choose some people as role models. Like you mention with the happy marriage. We look up to people, especially when we are young, for guidance, we are impressed and fascinated.
I still remember when Kurt Cobain died, not because I was a big fan, but because people went so crazy about his death. I didn't quite get it back then, I was only about 8 or 9 years old, but I understood something very important was taken from them.
Same happend when Lady Di died. I remember watching her funeral on TV. All those people on the streets... I remember how my Mum went on holidays to London on the weekend of Dianas funeral. She told me the whole city was absolutely quiet and people were crying on the streets. I know I didn't quite understand it - why would people cry when they didn't know her in person.
I do think it is an interesting topic. But for me personally, I only know strong reactions like that for people I knew in person.
But I can understand it. Also the feeling of betrayal. I think if we get very attached to a person, even if we don't know him/her in person, we want only the best for them. Want to keep them save, want them to only have the good things in life. I think love is an accurate term, even if it's an one-sided love, a love that's irrational. But the feelings we experience, they are what counts, and I'd say, to feel betrayal because of a new marriage, that's just an expression of how much we wanted the person we adore to be the one and only to everyone, forever.
But if we look at it rational, we might judge differently. Because then we see the real life happening and can say: yes, after four years, it is okay to move on. It doesn't mean somebody didn't grieve. But feelings aren't logical, and that's perfectly okay.
I wonder why our feelings are sometimes all over the place, even if logic suggests otherwise. I think we often underestimate the influence of our own hopes, wishes, even experiences...