Start by looking at your respective parents' marriages. We learn most of what we know by imprinting on the patterns with which we were raised. Certainly there is no way his desires can be considered if he is not more proactive on his behalf in discussing his needs and how his goals might realistically be achieved. Couples want and need to be understood by their spouses. It is usually out of empathic sharing that husbands and wives find their way to true and fair negotiation.
Marriage is a two way street.
Each partner gains from the goodwill their spouse experiences. Give and take is necessary for your relationship to thrive. Ask your husband to sit down and discuss the snowmobile with you. Find out how he feels about it and what it means to him to acquire one. See if you can catch the true essence of his desire for it, rather than whether or not the two of you will get one together.