So, the writers hated the marriage.
They kept trying to end it.
The fans loved the marriage.
Every time the writers tried to kill the marriage, the fans were outraged and the writers had to relent.
Marvel killed the marriage this time.
The fans were outraged.
Marvel decided to say "Eff you all! WE don't like the marriage, and we're keeping it gone!"
Marvel is in the customer service business.
Their customers want the marriage.
Marvel is refusing to service their customers.
Conclusion? Marvel writers are selfish.