Responses
Idk this isn't the most probably but yea it's sad
Haruka Tooki Ie
https://www.mangago.zone/read-manga/haruka_tooki_ie/
if you want angst and mental torture for yourself https://www.mangago.zone/read-manga/solo_for_two_mature/
This is not entirely make you cry or pain but it did hurt me..
And most of the sad parts are near ending so umm I'll just put it here if you want to read it hehe
https://www.mangago.zone/read-manga/be_the_bad_boss_s_man/
drop the most depressing/heart wrenching yaoi/bl you know, i wanna feel pain and cry myself to sleep lol