A movie from the 50's I think. A man who was married fell in love with a nice woman. The man's wife was in a mental institution. He had two children. Although he loved the "mistress" very much, he was too gentlemanly to divorce his wife who was in the institution. He did continue the affair and set up a lovely cottage on the ocean for her... either in England or maybe France. He would see her sometimes and they were very much in love. Then one day his wife died. It was raining. He was driving in the rain... free... to go to his mistress. There was a wreck. He died. In the end his children went to see her and you could tell they would be close and she would raise them. It was a real tear jerker, but I cannot remember the name. It used to be on late night T.V. Does anyone know the name??

I believe you are thinking of the movie Back Street, of which there are three versions, from 1932, 1941, and 1961. Apparently, each one ends a bit differently. The 1961 version with Susan Hayworth and Vera Miles concludes thusly:

"The situation has become untenable and Saxon decides that the only way to end the pain he has caused Rae is to kill his wife. He chooses a car accident, and of course we understand that the risk will be just a great for him. The wife dies, and Saxon survives – but only long enough to phone Rae and tell her he loves her." And then it seems that she takes in his kids.