[From my List "Strong male MC - part 1]
http://www.mangago.me/read-manga/weak_hero/
http://www.mangago.me/read-manga/omniscient_reader_s_viewpoint/ (my favorite)
http://www.mangago.me/read-manga/the_boxer/
http://www.mangago.me/read-manga/trash_of_the_count_s_family/
http://www.mangago.me/read-manga/noblesse/
http://www.mangago.me/read-manga/lookism/ (has it implied but she barely is mentioned in the webtoon)
http://www.mangago.me/read-manga/ranker_who_lives_a_second_time/
http://www.mangago.me/read-manga/lord_of_the_mysteries/
http://www.mangago.me/read-manga/kill_the_hero/
http://www.mangago.me/read-manga/eleceed/ (a bit implied but not focused)
http://www.mangago.me/read-manga/trapped_in_a_webnovel_as_a_good_for_nothing/
[From my list "strong male MC - part 2"]
http://www.mangago.me/read-manga/the_strongest_florist/
http://www.mangago.me/read-manga/mairimashita_iruma_kun/ (has romantic interest but she isnt annoying at all and their relationship is sweet cause they are both young)
http://www.mangago.me/read-manga/sss_class_suicide_hunter/ (apperently the love interest will be intruduced soon but its not yet)
http://www.mangago.me/read-manga/the_sword_of_glory/
http://www.mangago.me/read-manga/how_to_fight/ (has love interests but story isnt focused on her)
[From my list "strong male MC - part 3"]
http://www.mangago.me/read-manga/villain_initialization/
http://www.mangago.me/read-manga/the_player_that_can_t_level_up/
http://www.mangago.me/read-manga/villain_to_kill/
http://www.mangago.me/read-manga/return_of_the_frozen_player/
http://www.mangago.me/read-manga/dungeons_artifacts/
I'm feeling for him, I would not wanna be in side characters shoes