SOLVED. NA Romance book with flashbacks i read over 5 years ago. possible spoilers ahead

[livid]

FMC was in middle/high society.
there were flashbacks to her college days.
some specific scenes i remember from the flashbacks are her boyfriend at the time showing up to her dorm. (very scandalous so it was set mid 1900’s)
in current times set in an affluent beach scene.
i believe the fmc had a younger sister or possibly daughter called kitty or something like that.
another scene i remember was a flashback of her and her bf outside and it started to snow.

[livid]

A hundred summers