Uther did not even care about his wife and Queen at the time of Arthur's conception. This episode merely elaborated and concluded the point that the only thing that mattered to Uther was his legacy, which happily died along with him. The softer feelings he showed at times were just convenient to him and he was just relieved that Arthur was still loyal to him after he found out that his mother died because of his unnatural birth. This conclusion for Uther was one of the best I have seen for any character. Great episode.
Oh, and Uther... Guinevere is a top-notch Queen. When she gave that fake death sentence, I got chills XD