Actually, a wife's benefit is based on fifty percent of the husband's benefit before reduction for entitlement before full retirement age.

If your benefit based on your own work is less than this, you are eligible for your own benefit, and an additional amount equal to the difference between your own benefit and half the husband's.

If you begin receiving benefits at age 62, both portions will be reduced, but the percentage reduction is different for each.

is the benefit based on your ex's income while you were married to him?

There is a maximum amount that a couple can draw. Currently I believe it is $2,000 a month. You will have to talk to SS to see if you can draw the full 50 percent or if the $2,000 limit for a couple also includes the amount received by ex's.

example his amount is $1,000 she can draw $500 = $1,500

his amount is $1,800 she should be able to draw $900 however $1,800 + $900 = $2,700 but of that amount together they would receive on the max of $2,000. I am not certain what amount each would receive of the $2,000 they probably have a formula to calculate.

Depending on if drawing on your own record is more than half of his it is better to draw on your own. Because if there are cost of living increase in the future yours would increase but drawing on his the increased amount would only go to the maximum allowed.

To draw on your ex's you must have been married for a certain number of years. It used to be 10 or more so check with SS to get the factual information.

From what I have read, the maximum payment for a worker at full retirement age (66, in this case) is $2346. However, each person's benefit is based on his own work record. The average payout is actually much less. A spouse has the option of taking the amount of: her/his own benefit or if less than the percentage based on the spouse's income, taking that amount. Basically if the husband's benefit at full retiremnt age is 1000, the wife would be entitled to an amount of 500. If she worked and her benefit from working is greater than 500 she would draw only her benefit; if her benefit amount is less than 500, then she would draw her amount (say 375)plus an amount to equal the 500. If she hadn't worked, she would be entitled to the 50% amount of her husband's benefit. This does not reduce the husband's benefit. The percentage is based on full retirement age; and the percentage is reduced for each year less than full retirement age.

That is not the maximum family benefit, which is based on a widow/widower with minor or disabled children. Per SS site: "The benefit amount you and your children receive is based on your deceased husband's earnings. The more he paid into Social Security, the greater your benefits will be. However, there is a limit to the amount of money that can be paid each month to a family. The limit is normally referred to as the "family maximum." This limit varies, but it is generally between 150 and 180 percent of the deceased's benefit amount. If the sum of the benefits payable to you and your children is greater than this limit, each of you will receive a benefit amount that is proportionately reduced"

socialsecurity.gov has many Q & A's

Here is a link that might be useful: SS Benefits spouse