I really haven't seen any chemistry between Mary and Henry. It seems like Tom is more interested in Henry, or rather Henry's car. I don't know why everyone is acting like this is the man for Mary, when Mary and Henry have only spend a few brief periods of time together.
I hope that Edith ends up happy with Bertie. I really like Bertie, and think he'll fit in with the family well. He's also the sort of guy who wouldn't be upset learning the truth about Marigold.
I hope that in the end Mary and Edith become friends. They are both old enough to put aside their childish antagonism. Mary will always be a snob, but she can be nicer, as she was when she was with Matthew. Edith can get over her inferiority complex, and Bertie is the man to help her see her worth. When she feels better about herself she'll be in a better place to fix her situation with her sister.
Yes, that was brutal and uncalled for. Also, he was a guest in her home, and was incredibly rude to talk to his host that way.