What is interesting is that Roland meets Susan before his "tower infection." He is not compelled to embark on his quest until he becomes trapped within the grapefruit. I think it is possible that her and Cuthbert might have wound up together and would have probably been much happier- though not as intense. I think that is part of what King is trying to reveal in Roland as a character throughout the novel- as Susannah suggests at the end of Roland's tale, He understands Susan's death as a consequence of his quest for the tower. That drive in Roland is what made him and Susan perfect for each other but also doomed "Ka like a wind." Cuthbert did not have that same drive and this is one of the reasons he was such an enigma to Roland at times. How could you laugh in the midst of such a desperate and brutal existence? Cuthbert would have made a much better husband- Roland however, wasn't made for that lifestyle. Remember that Roland decides not to marry Susan after going todash within the grapefruit and seeing the tower for the first time. Cuthbert would not have had that response.