Unlike child support, spousal support is often very difficult (if not impossible) to modify after the divorce is final, so getting it right the first time is a must!
Given your length of marriage and the disparity in income, you are probably a spousal support candidate. For how long depends on the state you live in.
If you live in Texas, it's 3 years unless there are very extenuating circumstances. Most other places, it's 1/3 to 1/2 the length of the marriage.
If you need it, ask for it when you file for divorce.