Which sad or angst-filled romance book literally made you cry?

A lot of book reviewers, when they advertise a book or talk about it, mention that it made them want to cry or that it was very heart-wrenching. But I don’t want that heavy feeling in your chest only. I want to know which books REALLY made you cry, or shed a tear, and if you're okay with telling why it made you cry, please share! But be sure to not spoilt it or cover the spoilers, of course.

Honestly, I'm asking because I've never literally cried over a romance book, but I'm curious to see which books have affected other people so deeply.