Five couples: Justin and Flora, Morgan and Catherine, Bramwell and Daphne, Kendrick and Melanie, and Bramwell and Catherine. All of them different and interesting.
Justin went into the Room ten years ago, so I figure Flora had at least fifteen years of marriage with him before he became a different person. She had at least fifteen years to solidify her position at Collinwood, she had three sons with Justin, and she was no longer young by the time she lost Justin to the Room.
Catherine's position is quite different from what Flora's was. She's new to the house and new to the concept of the Room, and she is the beneficiary of a sacrifice that she never asked her husband to make for her. Of course she feels guilty that Morgan sacrificed himself for her - but I imagine a big part of her is thinking, "I was going to destroy that so-called Curse, and Morgan wrecked everything!"
I shouldn't feel sorry for Daphne, but I do. She walked into her marriage knowing Bramwell couldn't be over Catherine yet, but, as she said, she wanted it so very much. This might have been her only opportunity to make it happen, and, although I daresay DarkLady will disagree with me, I think Daphne had a reasonable chance of making the marriage work, if only Catherine hadn't dropped that baby bombshell on Bramwell within hours of Bramwell's and Daphne's wedding. If it hadn't been for that, Bramwell might well have stayed angry with Catherine long enough for Daphne to establish some rhythms and routines in the marriage - enough for things not to go spectacularly bad spectacularly soon.
Kendrick thinks Melanie couldn't have killed Stella. I think he's wrong, and I also think he doesn't know as much as we do about the murder. As far as we know, only three people knew Stella was locked up in the Tower room: Flora, Julia, and Melanie. At this point, in dramatic terms, any one of them could have done it, and we could get a satisfyingly shattering dénouement. (I want to see Julia confessing!) Or we could find out that somebody completely unexpected witnessed Flora, Julia, and Melanie coming out of the Tower room and came back later to murder Stella. But in terms of cold logic, the most likely murderer is Melanie. Kendrick's just believing what he wants to believe. As I said yesterday, Kendrick's not all that bright. If he and Melanie marry, I think Melanie is going realize someday that she's smarter than her husband, assuming she doesn't kill him first. It would be interesting to see her dealing with that realization.
Bramwell and Catherine. Just throw them both off of Widows Hill, OK? I still adore Bramwell, but they're neither of them civilized enough to live.