I wish I had more advice but I don’t. I will say, you are entitled to your feelings and they are valid. Just because your partner has cancer, doesn’t mean your feelings and needs get out on hold. You’ve gone through a battle right along with him, all while experiencing loss. You don’t sound selfish at all. You sound like a human being who is hurting and scared. Have you thought Of counseling ? It may help you to have someone else validate your feelings. It sounds like you are doing self care, which is great! your husband can schedule an appt with his doctor to figure out what’s going on with the breathing!