This is totally my guilty pleasure manga: https://www.mangago.me/read-manga/there_s_no_way_this_is_fate_newlyweds_arc/ (This is technically the sequel, but I like it better than the first volume. It’s sillier and more lighthearted)
https://www.mangago.me/read-manga/i_wanna_die_before_i_m_30/
https://www.mangago.me/read-manga/aisaretagari_no_gemini/ (this author has other threesome story but it's on going)
https://www.mangago.me/read-manga/aisare_neko_wo_hantoubun/
https://www.mangago.me/read-manga/one_two_three_1/
https://www.mangago.me/read-manga/futarijime_underdog/
https://www.mangago.me/read-manga/high_key_x_low_key/
Yup, already read this before thanks!
Recos for threesome couples? No painful love triangle where the mc only ends up with one of them.