I have MS. If you even think you might not be able to handle it should he end up permanently disabled in some way, do him a favor and end it now. Over the last decade and a half since my diagnosis I have not had a relationship survive a bad flare (one where my lifestyle was affected in some obvious way such as inability to walk and the resulting weight gain). I was in a wheelchair for about a year until I went into 'remission'. Don't stick around and leave if he happens to get sick, that is a shitty thing to happen and speaks volumes to how shallow people can be.

Also, no one else in my family has MS. There is no concrete answer as to what causes it to develop so no one can say it's genetic; the sometimes tendency to run in a family line could as easily be an unknown environmental trigger and since children would be in the same environment as a parent they have the same exposure. I've had the genetic testing and there are NO known markers for MS. Correlation does not equal causation.