No. If you are healthy, living a clean lifestyle and eating a good nutrient dense diet, I don't understand why you were supplementing with methylfolate and B12 anyway, except maybe as some kind of "insurance".
The CBS mutation (or any of the methylation SNPs) are not automatically "activated" just because you have them. They also require environmental toxins, viruses, or extreme amounts of prolonged stress to become an issue.
Even if your CBS was "activated" you would only have to restrict sulfur for a few months - long enough to remove the excess sulfur stores and get the transsulfuration pathway working again.
You can do the HDRI Methylation Pathways Panel to get a measurement of the functional status of your methylation pathway. This will tell you if things are operating correctly or not.
So, if you're otherwise healthly and feel good, I would keep doing what you're doing. However, since our world is so toxic, I would also pay particular attention to eliminating toxins from your environment. So that means living as if you had MCS - so be careful about household cleaning products, paints, markers, new furniture, remodeling, new car, etc. All these things will offgas formaldehyde and other compounds and deplete glutathione.
I would also suggest making a FIR sauna or other methods of detoxification part of your daily routine. This will detox out chemicals and metals which your body would otherwise squirrel away in your fat.
ps. since your and your wife are both CBS +/+, all of your children will also be CBS +/+. There is a neat little chart on the Heartfixer page, that will give you an idea of what SNPs your children might have, based on what the parents have.
http://www.heartfixer.com/AMRI-Nutrigenomics.htm