That's so mean and uncalled for.  When partners want to finish a relationship they always blame you for their decision because they are cowards.  My Dad left and blamed Mum for everything but he was seeing someone else, so cowardly.  My brother left his wife and he blamed her for not being social enough, he was seeing someone else, coward.  So you don't say if there were already problems in this relationship as she has made a point of using the cancer as a reason.  If you love someone a scar would not matter, my husband had his leg amputated but I still love him, he has cancer as well but I'm still with him.  Please don't let her bring you down and blame you, you have coped with so much and deserve better.  Post again if you need to.  All my best wishes, Carol