Parents/Family try to break them up
http://www.mangago.me/read-manga/neo_arcadia_yami_ni_saku_niji/
http://www.mangago.me/read-manga/fuson_na_hana_o_aisureba/
http://www.mangago.me/read-manga/uchi_no_tantei_shirimasen_ka/
http://www.mangago.me/read-manga/katekyo/
http://www.mangago.me/read-manga/kishidou_club_bangaihen/
http://www.mangago.me/read-manga/gochisousama/
http://www.mangago.me/read-manga/sick/
http://www.mangago.me/read-manga/memory_of_the_future/ - Prequel
http://www.mangago.me/read-manga/kaze_no_yukue/ - Sequel
http://www.mangago.me/read-manga/follow/
http://www.mangago.me/read-manga/ani_no_hanashi/
http://www.mangago.me/read-manga/neji_no_kaiten/
http://www.mangago.me/read-manga/kanashii_kotoba/
http://www.mangago.me/read-manga/tatsu_no_otoshigo/
http://www.mangago.me/read-manga/mijuku_na_karesh/
Kuroneko Series too
BL where the parents find out about the relationship and are against it? Like to the point where they try to split them up?