My wife and I are both retired and we were both born in 1948. My wife took Social Security at 64 and I took a spousal benefit on her account until I was 70 and then I took my full Social Security. I read that she might be able to apply for something called "spousal supplement" (not "spousal benefit"). I don't know if this would be more than we are now getting. My (husband's) monthly check is $2840 and my wife's check is $1083. Can you shed any light on any benefit from my wife applying for a spousal supplement?
'Spousal supplement' isn't an actual Social Security benefit type. It's simply a term used by some people to describe an excess Social Security spousal benefit, which in turn is a descriptive term for the partial spousal benefit that is sometimes payable to the lower earning spouse when both members of a couple are drawing benefits on their own records. In order for your wife to be eligible for an excess spousal benefit from your record, your primary insurance amount (PIA) would have to be more than twice as much as your wife's PIA. A person's PIA is the amount of their Social Security retirement benefit if they start drawing at full retirement age (FRA).
Based on the information in your question it doesn't sound like your wife would qualify for an excess spousal benefit. If she filed at age 64 and her reduced benefit rate is $1083, her PIA could be anywhere from $1159 to $1250 depending on whether she started drawing right at age 64 or sometime between ages 64 & 65. And, if you started drawing your Social Security retirement benefits at age 70 and your benefit rate is $2840, then your PIA must be approximately $2151 (i.e. $2840/1.32) since your age 70 rate would be 32% higher than your PIA. Therefore, since your wife's PIA is apparently more than 50% of your PIA, she probably doesn't qualify for an excess spousal benefit. Note, however, that I can't say that for certain because I have only the limited information in your question to go on. Your wife could find out for sure whether or not she qualifies by contacting Social Security and filing an application for spousal benefits.