Her husband, Leon, was diagnosed with the condition three years ago, and, on Saturday, Sam, 39, will do a sponsored skydive in aid of the MS Treatment Centre, in Southwick.
“We were in complete shock for a long time after we were told,” said Sam, of Alexandra Road, Worthing.
“I don’t know if we are coping with it.
“You can’t plan anything.
“He can be fine, walking, talking, working, and then, all of a sudden, he can’t do any of those things.
“Leon has been an inspiration to us all, and is the bravest person I have ever met.”
She added the couple’s two boys, Joe, 11, and Zac, 10, had been “incredible”.
Multiple sclerosis affects the central nervous system.
About 100,000 people in the UK, mainly between the ages of 20 and 40, suffer from it.
Symptoms include dizziness and balance problems, extreme fatigue and issues with eyesight such as double or blurred vision.
Sam, who has been with Leon since she was 16, said she wanted the fruits of her fund-raising to go to a local cause.
“The MS Society gets a lot of funding and I wanted to do it for a local place,” she said.
“Leon has not needed to use the centre yet, but we know about how much help it gives to people in the local area.”
She added she was sure the family would need the centre’s services in the future.
So far, she and Jo have raised more than £650.
Anyone who would like to add to the fund can go to www.virginmoneygiving.com/team/samandjo