Imma share my list of favorite tearjerkers. The last one especially is like what you described. They love each other so much, but are forced to... well I'll let you read it yourself.
https://www.mangago.zone/home/mangalist/2241244/
https://www.mangago.zone/read-manga/murderer_llewellyn_s_enchanting_dinner_invitation/
This one is one of my ultimative favorite BL pieces ♡. This manhwa is emotional and can be quite funny. The further you read this story, the better it will be after some things will be explained... (I don't want to spoil anything). Especially the flashbacks to their past will become extremely painful to read. Their love is so strong yet both of them are broken people.
MC is someone who is grumpy yet very lonely and affection-starved, and his lover is a yandere and his stalker.
Can someone recommend me some good angst i wanna cry myself all night anything is good gl, bl or straight as long as its angst (and I don't want that toxic abusive love or anything like that i want the where they love each other so much but they cannot be together or the partner suddenly dies in a incurable disease or got into a accident if knows a story like i would really appreciate it if can give it to me im starving) tysm mwah, sorrry for the long paragraph hehe.