A short search here on trakt reveals that the idea for this movie is anything than somewhat original. However, I haven't seen the 2008 (Flemish) or 2010 (Dutch remake) version, nor maybe any other one that may exist under a different name.

But I must say a very intriguing story and one of the best movies I've seen in a long time. Mainly because of the great cast and their acting. What'd you expect from Karl Urban (Almost Human, great series, cancelled way too early) or Eric Stonestreet (Modern Family).
The story is nicely told with flashbacks and had me guessing what happened and who is responsible and still was able to surprise me. Although it should have been kind of obvious that it was that person. James Marsden and Wentworth Miller are also very well known faces and fit in here very well.
The great thing about this story is that basically every single person would have a motive.
And as if one plot twist wouldn't be enough it houses another one that bugged me as soon as it happened. The insulin incident.
While it is heavy on dialogue, explaining a lot and not action driven, I'd highly recommend it, if you don't know the story yet and prefer story - although not overly complicated - over action.
Surprisingly it has a rather averaged rating and a bad one on Metascore, where it is rather criticially panned. Some of the criticism is valid, though. Especially regarding the wives, but well.
See for yourself on what side you are on.