I discovered recently that someone I was once deeply in love with had died. It was clear he remained to the end the person, who had meant so much to me, but he had developed rheumatiod arthritis in his 40s, had to stop work a few years later and was severely disabled for the last 25 years of his life. His career had taken him to a part of the country a long way from my family.
If you love someone you cope, and do not know what an alterantive life would have been like, except, possibly, one without the illness. But I would be less than honest if I did not say that the life I have actually had, despite its various problems and catatstrophes has been more varied and interesting and less onerous than the one I might have had and for some years longed for.
Even if you went back in time, you would still have very little control over the outcomes.
Be careful what you wish for.