The questions I get about Social Security have made it clear how incredibly complicated this benefits system can be. So here’s a little story to illustrate one important facet of Social Security: spousal benefits.

Jack was a charming guy—maybe too charming. He enjoyed the ladies and the ladies enjoyed him, at least until they discovered they weren’t the only ladies in his life. This led to more than a little drama, and a few divorces.

Jack first married at 20, to Mary. Their marriage lasted 10 years and produced two children before breaking up. Mary went on to marry again and had a happy 30 years until her second husband died.

Jack’s second marriage was to Anne. That lasted five years. Anne never remarried.

After a few years playing the field, Jack married a third time, to Jo Beth. They separated after nine years and divorced a couple years later. Jo Beth remarried and had kids with her second husband. This marriage also ended in divorce after thirteen years.

For the past decade, Jack has been happily married to Dianne. Both are 62, but Jack has decided not to retire for a few years (all those divorces took their financial toll).

Now for the question: which of Jack’s wives qualify for Social Security spousal benefits based on Jack’s earnings record?

The answer: Mary and Jo Beth. Both were married to Jack for at least 10 years, and neither is currently married. Mary and Jo Beth also would be eligible for benefits based on their second husbands’ records (Mary as a survivor, Jo Beth as a divorced spouse) but they wouldn’t be able to claim more than one benefit. They would typically get whatever benefit is largest: the one based on Jack’s earning record, the one based on the second spouse’s earnings record, or the one based on her own earnings record.

Why wouldn’t Dianne qualify for spousal benefits, since she’s the current spouse? Because Jack hasn’t applied for his own benefits. That doesn’t matter to the former wives, since the ex’s cooperation isn’t required for them to start getting spousal benefits. The ex merely has to be old enough to qualify for retirement benefits (which you typically are at age 62.). If you’re currently married, though, you can’t start spousal benefits unless your “earner” has applied.

Jack could allow Dianne to start benefits with a technique called “file and suspend,” in which he would file for benefits and then immediately suspend his application. That would allow his own benefit to continue to grow while allowing her to get checks based on his earnings record.

So conceivably, three women and Jack himself eventually could be earning benefits based solely on Jack’s earnings records. The amounts the women get wouldn’t affect or reduce each other’s benefit, or his.

Most people can’t squeeze quite that much mileage out of the Social Security taxes they pay. But since spousal benefits could result in a bigger check than you might get on your own, they’re worth knowing about.