64 here - not even married yet! (he makes me research stuff - but I enjoy it, so got full credit for learning new stuff as a result of the partner! LOL) He still makes me giggle and laugh...and does not really piss me off. Our strengths & weaknesses complement each other's...maybe a first born, last born or yin-yang thing...who really cares - it works, and I like it!
Ha - she's awesome...good luck with your relationship musings