Chatty, I doubt there is an age where I would say a person was too old to marry, assuming one wants to.
But as we get older and we have assets we want to preserve for our children, it sometimes doesn't make sense financially to legally tie the knot, especially since we will not likely be raising children anymore.
In those cases, it might make more sense just to live together...
But this is just my opinion.
I am speaking as an observer of my 81 year old father, who has been married - and divorced -- three times. Each divorce has taken a financial toll on his assets. (As well as a toll on his heart, I am sure...)
These days he has a "significant other," and they travel together for months at a time - and spend a lot of time together when they are not on the road.
But each of them maintains their own household.
Last I spoke with him, he said he figured he has about four more good years of traveling left in him. (He and his lady just bought a new travel trailer to pull behind his Tahoe and they plan to divide up the US into quadrants and visit all the national parks during these coming years.)
But at 81 he is agile, fluent and alert. He still briskly walks several miles a day -- and I have a hard time keeping up with him whenever I've tried to accompany him.
So he is clearly in good health, and, if were to tell me he wanted to marry again, I'd say "go for it." I'm sure loving and supportive companionship - not to mention sex if so desired - is still "good medicine" for all of us, no matter how old we are.