Let your fears be put to rest. Your husband will be better soon- with or without medication. Over 26 years has passed since I was diagnosed; I never took any medication, including steroids. You can live a fruitful life with or without medication. I am now on disability after my 20th year of MS. I live one day at a time.
As a spouse, might I recommend that you read a little about MS. You can get equipment or reading material on loan from the MS Association or the MS Society. Take the time to inform yourself. I try to follow the S**** diet, stretch my muscles every day, and watch for my triggers (those things that can bring on an attack). Nowadays the doctor has me using passive exercise to rehabilitate my left leg which has much nerve damage.
Lifestyle changes are indeed needed, but the changes need not be drastic.
Your husband does not need any pity. Though it may be difficult to see him trying to walk with difficulty, you must let him ask for help. I realize it is an overwhelming emotion for you, but you must try to be objective. The less of a "big deal" you make it, the better your husband will be.
You live in Florida, so the heat may play a factor (each of us is different). Avoiding the heat of the day is the best thing for me to survive the summers. As a caregiver you should be aware of any overheating that can rapidly occur. I have a cooling vest that I wear outside during the summer if I must be out. I also have a cooling hat. Believe me, it works wonders!!
Your biggest concern right now is your own fear. Please know that MS is not fatal (there is a very VERY rare type that is fatal but it is EXTREMELY rare).
Please note, too, that you need to sit down with your husband and objectively decide on what things stress him out the most. Those stressful things need to be avoided. If cognitive impairment happens, you might also need to assume some things he has done. For me, balancing the check book and shopping and budgeting, my wife does. These seemingly simple tasks overwhelm me. Find out what overwhelms him.
Please keep in mind that his emotional threshold may be weakened. He may have days where he cannot stand a certain sound or cannot stand to be around people. These days, I have them, are trying. On those occasions, your husband needs a retreat within the home where he can convalesce. Even one day alone can perform miracles and allow the family to remain emotionally intact.
Multitasking for me- no longer an option. I used to multitask as a general manager of a Japanese corporation. No longer an option. My brain can only process so much and I lose focus and shut down when too many things are happening.
Driving a car- I use hand controls. These hand controls have helped me maintain my independence. If your husband has leg issues, I would recommend hand controls. I have been using them since 2002.
Stay positive and stay encouraged. I walk closely with my Creator and He helps me each day. Remember to take baby steps- BUT do not "baby" your husband. The only thing that has changed is his speed. MS is not fatal, it just slows you down. Each day can bring a multitude of blessings. In the meanwhile, I will have both of you in my prayers. You might also show your husband this web site. Guys do not always want to ask for help from their spouse, but he might ask advice here.

Welcome to the boards!!