I'm a sucker for tear-jerking romantic movies and to be honest I quite liked this one, though there was this little voice in my head continually saying, "oh, c'mon, are you going to swallow still another contrived coincidence?!" But with a "willing suspension of disbelief", as I said before I quite enjoyed it.
The good things first: all the major actors acted superbly and the scenery is simply awesome. The love between the hero and the heroine is depicted tenderly and beautifully. Isabel's pain on losing her two babies in tragic miscarriages is palpable. Michael Fassbender's hero is restrained and believable and his character's moral rectitude is evident without any preaching.
Now for the problems. I couldn't help wondering how Isabel made a play for the silent hero after just a single meeting and how fast he surrenders to her charms and whisks her off to his solitary lighthouse. Her character too, after a while becomes selfish and cruel unable to see that she has assuaged her own pain after two heartrending miscarriages, by inflicting the same pain on an another mother. She emotionally manipulates her husband and forces him against his conscience, to lie that the baby they find drifting in a boat is theirs. She also has no qualms in condemning him to jail and perhaps death because he is unable to live with his guilty conscience and is instrumental in returning the child to her own biological mother.
The coincidences of seeing the child's mother weeping in the cemetery at Lucy/Grace's christening and at the lighthouse function and the rather jaded and forced device of using the child's rattle as the instrument of dénouement is tiresome to say the least. Also there is no explanation why Hannah, the child's real mother , after promising in a poignant prayer that she'll put the child's interests first, never apparently lets her contact Isabel or her husband. It is only after Isabel has expired that the adult Lucy/Grace reaches out to the man who could have at least partly filled the paternal role in her life.