A few of these are interesting to me.
My stepmom never married my dad - because she was collecting spousal from her deceased husband's acct. (The were registered domestic partners instead.) My dad would have lost his surviving spouse part of my mom's pension. Getting married would have been a big hit to their income streams. They were in their 70's when they did the analysis NOT to get married.
The math was clear for us for my husband to take SS early - since we have minor age children. That's something I learned from THIS board - but the article reiterated it.
Lots of different scenarios to ponder.