Lasting marriages/relationships do still happen in real life. I've been married over 20 years, my brother over 30, my nephew over 10. My parents were married for over 40 years. And it actually happens in Hollywood--Goldie Hawn/Kurt Russell, Meredith/Richard Viera, Joy Behar/Steve.
I'm sure a lot of people think Clarissa is emotionally satisfying. Some probably think she gets what she deserves. It's NOT the sort of ending I look for. Written in 1747-48 by Samuel Richardson, it was made into a movie in the '90s starring Sean Bean. Clarissa is in the public domain and can be downloaded free at sites like Project Gutenberg (http://www.gutenberg.org/).
Personally, I don't like the HEA tag. It implies a perfect world like a fairy tale. But I like to think the characters are committed enough to work through their problems and remain together. At the first sign of trouble, they're not going to run out and get a divorce, which seems to be so prevalent nowadays. (Don't get me started on those Hollywood folks, who change spouses quicker than some of us change shoes.) Then, some people will think I'm crazy since they're only fictional characters.
We all have expectations for the books we read. In a mystery the murderer is caught and justice is done. Villains are stopped. In a romance the hero and heroine stick together through thick and thin. So what are your expectations for endings? Can a character's death satisfy you emotionally?