Heavy boyfriend
https://www.mangago.zone/read-manga/merry_psycho/ (she a bit crazier)
https://www.mangago.zone/read-manga/i_said_i_d_love_you_to_death_didn_t_i/
https://www.mangago.zone/read-manga/red_mansion/
https://www.mangago.zone/read-manga/i_love_you_kyouko_san/
https://www.mangago.zone/read-manga/head_over_heels/
https://www.mangago.zone/read-manga/beasts_of_desire/
https://www.mangago.zone/read-manga/murcielago/
https://www.mangago.zone/read-manga/you_are_still_in_a_bird_cage/
https://www.mangago.zone/read-manga/zenbu_kowashite_jigoku_de_aishite/
https://www.mangago.zone/read-manga/pumpkin_night/ (ml becomes crazy over time)
https://www.mangago.zone/read-manga/the_menhera_rabbit_is_adored_by_the_yandere_wolf/
https://www.mangago.zone/read-manga/how_to_break_up_well/
https://www.mangago.zone/read-manga/to_hunt_the_stalker/
Romance where both are bad shit crazy