I know many yaoi mangas that you're describing but none of the titles are coming to my head. Goddamnit.
I was about to fall asleep.. but I saw you read only 19 days.. So I tried to find some for you..
After having affair then for some reason they're apart..
http://www.mangago.zone/read-manga/taiyou_to_himitsu_secret_and_sun/
http://www.mangago.zone/read-manga/puchitto_hajiketa/
http://www.mangago.zone/read-manga/ookami_shounen_to_hamu_no_hito/
http://www.mangago.zone/read-manga/escape_journey/
http://www.mangago.zone/read-manga/doubt_nishimura_shuuko/
http://www.mangago.zone/read-manga/trap_ootsuki_miu/
http://www.mangago.zone/read-manga/bond_z/
Yaoi or BL manga where the mains had a past relationship and are meeting again for the first time a few years later? And their lives are probably very different now but eventually they rediscover their old love? (Idk if this it too specific lol) thanks!