Very sad. Been a fan of Marvel comics since I was at school.
My missus works for a publishing company which holds Marvel licenses, and her boss was good friends with Stan Lee and his wife, and had known them for many years. Whenever she would speak to Stan, she said he would speak so glowingly of his wife almost constantly, and almost everything he did he credited to her driving him on. She said that when his wife sadly passed last year, she thought he wouldn't be too far behind. Not the boldest of predictions given his age, obviously, but still very sad to hear about both her passing and now his.