Hi Soon To Be Wife,
I think you should talk to your husband's doctor and ask if he should be reclassified as a thal intermedia, as a major would not be able to discontinue transfusing after a splenectomy, while treatment for thal intermedia has traditionally included splenectomy to reduce or eliminate the need for blood. Since both major and intermedia normally refer to thal where both Hb genes are defective, the distinction between major and intermedia is not always clear. If he hasn't transfused for over three years, it is likely he is actually intermedia, which can almost be described as thal major lite.
Can you tell us what your husband's hemoglobin range is? If he gets by on a low level he may need to watch for iron buildup from his diet, as excess iron can be absorbed by the gut if the Hb is low. Osteo has been a problem in thals and regular bone density scans are recommended, but with today's drugs, it is a manageable problem that can even be reversed.
There are many problems related to thal and you can read about many of them on this site and also ways to deal with them. The really positive thing is that your husband is not transfusing and is doing well. He needs a good diet and some supplements like folic acid and I think you both can benefit by reading some of the discussions on our boards. It is important that his doctor understand thal well, so that if any problems do begin, they can be recognized and treated. There is no reason to believe your husband will not lead a normal life.