Anyone recommend any old people romance? Like they loved another person or have been marri...

https://www.mangago.zone/read-manga/sui_mo_amai_mo/

Hope these help!

https://www.mangago.zone/read-manga/sesame_salt_and_pudding/

https://www.mangago.zone/read-manga/first_of_summers/

https://www.mangago.zone/read-manga/shoushin_otoko_ni_haru_no_arashi/ (not 40+ but yeah is older than seme)

https://www.mangago.zone/read-manga/koi_ga_ochitara/

https://www.mangago.zone/read-manga/sui_mo_amai_mo/

https://www.mangago.zone/read-manga/life_senjou_no_bokura/ (not exactly what you are asking for, but they found each other again when they are in their late 30s)

https://www.mangago.zone/read-manga/love_nest_minaduki_yuu/ (I don't think he is 40+, maybe in his late 30s, I don't remember lol but seme is old)

https://www.mangago.zone/read-manga/on_doorstep/

https://www.mangago.zone/read-manga/koi_wo_suru_tsumori_wa_nakatta/ (uke is 30, not that old lol, but story is good)

https://www.mangago.zone/read-manga/oni_to_tengoku/

https://www.mangago.zone/read-manga/midnight_rain_ctk/

https://www.mangago.zone/read-manga/itooshiki_hibi/
https://www.mangago.zone/read-manga/40_x_40_chikuwa_kaigi/
https://www.mangago.zone/read-manga/it_can_t_be_mutual_love/
https://www.mangago.zone/read-manga/jijii_no_koi/
Enjoy