TL;DR It's perfectly watchable if you don't think about it too hard, but unfortunately the wife has to take stupid pills to make the decisions and assumptions she makes and it took me out of the movie on a few occasions. The movie's theme was incomplete. This is the writer's fault, not the actors.
-----SPOILERS BELOW-----
The issue I'm noticing in the vast majority of the reviews is one of theme, because a lot of people--rightly--point out that Henry was supportive of his wife, so his death at the end felt strange. And again, that's the writer's fault. The script wants us to ask the question, "Who is controlling whom in this relationship?" But they didn't thread the needle, and the movie fell flat.
The husband, Henry, is an architect. He designs their gorgeous house and puts it in the middle of nowhere. That's a huge control-move; he was able to build the house however he wanted, and he chose to put a dungeon in the basement. He kidnaps a victim and threatens to kill her "when he decides". He gives Meera a clock figurine, almost a wordless statement of the same thing, "I decide when." He dresses impeccably, not a hair out of place. It's all about control.
But the problem lies with how the script treats Meera and her cancer experience. We're supposed to think that Henry was the supportive, loving husband through her illness, and there's an implication that his love and care could border on obsessiveness. But we don't SEE that. Because she holds down a job, leaves the house all the time, and makes decisions for herself. We don't see him manipulating her, so her dumbest decisions in the movie aren't understandable. They are 100% her fault. So...does Henry have too much control or not? Who are we rooting for? The movie is unclear.
I'll wrap this up. One way they could have fixed this theme issue would be to have made Meera still ill, whether with breast cancer (as in the finished film) or something else. Take away her job, no ability to leave the house as easily. Then Henry's loving, supportive behavior could eventually morph into control, and the stakes would be MUCH higher because Meera is trapped in an isolated house--that HE designed--with a man who is unpredictable. The audience would root for her more readily knowing that she is physically less able to escape, and her turnaround to eventually overpowering and killing her husband would be more thrilling, suspense-filled, and cathartic.
Pay attention to theme, kids. It matters.