https://www.mangago.me/read-manga/boku_no_omega_yo_samenaide/
so the story I pasted is about a Kindergarten teacher "Ao" and his 'TWIN' brother "Midori" who are 'UKE' omegas...Midoris married to his mate and Ao finds his mate thru chance, a Young handsome rich smart seXXXy capable alpha..
https://www.mangago.me/read-manga/hatsukoi_no_kanata/
this link here is the prequel. It's when the kid is grown in UNI and falls in love:)