...first of all, let me correct myself: you're not in love with 'a chronic illness', because an illness does not define a person. You are in love with someone who HAS a chronic illness. it is a part of them, but is not their entirety. It is not their label. It is not their purpose or defining character.
Their interests, their hobbies, their smile, their eyes; their humour, their intelligence, their sound, smell and taste. That's what you are in love with: a person. A human, and you're damn lucky if they love you back too. Love is a beautiful thing. It can be monogamous and instantaneous for some - like love at first sight. Or you can engage with different people across different periods of your life... love is beautiful, and needs to be cherished and respected.
But what happens when you are in love with someone who has a complex chronic condition, mental or physical? Whether you meet them with it, or they develop to have it during the relationship... here is some solid advice from someone - myself - an individual with multiple chronic conditions, to you: a person with a heart, a brain and a soul.