Though their marriage was loving, some biographers suggest they viewed one another more like a brother and sister.
Lies are how historical beloved figures are saved from disillusioned trash heaping by latter day morality dictates. Where the romantic inclinations toward someone "too young" is concerned, just explain away what is obvious and documented. They did this to LC as well.
Highborn kinsmen approve of such revisions, or at the very least, tearing out relevant diary pages.