I believe it is like some other diseases, while it, itself is not fatal, because of it complications can arise that are.

I was told upon diagnosis that MS was not likely to be fatal.

I've heard it could effect your breathing and cause death by suffocation. If it's true I hope it's rare. If it's not true, let me know

Not generally fatal , more the complications that can arise are .

True, however it is an autoimmune disease and can lead to other conditions that are fatal if not diagnosed and/or treated.