
Here some that somewhat like that, there some form of adoption:
https://www.mangago.zone/read-manga/boku_no_papa_to_papa_no_hanashi/ (This one is where a established couple adopted a baby)
https://www.mangago.zone/read-manga/family_now_and_forever/
https://www.mangago.zone/read-manga/ibitsuna_bokura_no_katachi/ (adopted child)
https://www.mangago.zone/read-manga/itoshii_hito_saku_minori/
https://www.mangago.zone/read-manga/ookami_papa_wa_hitsuji_tsura_shite_yatte_kuru/
https://www.mangago.zone/read-manga/sekai_wa_shippo_de_dekiteiru/
https://www.mangago.zone/read-manga/motoyan_papa_to_hitsuji_sensei/
https://www.mangago.zone/read-manga/kazoku_ni_narouyo/
https://www.mangago.zone/read-manga/dekichatta_danshi/
https://www.mangago.zone/read-manga/oh_my_hero/
https://www.mangago.zone/read-manga/family_simulation/ (2nd coupe is a meh, some people didn't like them)
https://www.mangago.zone/read-manga/bokura_no_shokutaku/ (this is to cute, not to add and there's a drama)
https://www.mangago.zone/read-manga/papa_no_sukinahito/
https://www.mangago.zone/read-manga/motoyan_papa_to_hitsuji_sensei_yotsuba/
https://www.mangago.zone/read-manga/take_to_kota_to_aoto/
https://www.mangago.zone/read-manga/tabun_korekara_ai_no_hibi/
https://www.mangago.zone/read-manga/daraku_kazoku_ron/
https://www.mangago.zone/read-manga/itsuka_kazoku_ni_naru_made/
https://www.mangago.zone/read-manga/tsukiatte_nainoni_fuufu_yattemasu_pcbs/
https://www.mangago.zone/read-manga/papa_to_watashi_to_ayumu_chan/
https://www.mangago.zone/read-manga/kiraide_isasete/
https://www.mangago.zone/read-manga/papa_x_papa_to_de_sorezore_yattemasu/ (wholesome omegaverse)
This is beautiful
But I want the JP BLs to stop with that whole “oh but you will know true happiness when you will get married and have kids” like there are a lot of miserable people who are married with kids. I’m tired of seeing this to create drama in BLs