When seme (or male lead if it's shoujo/josei manga) regretting all the bad thing he has done (especially to his significant other) and trying to make amend of his wrongdoings. Some of the list has uke that is very forgiving, never forgive or died. I don't mind whichever ending, it's just the feeling of regret, from doing bad things or taking things for granted.
Most in the list are yaoi/shounen-ai genre, that's why I used term 'seme'. Feel free to add if you have anything similar in mind.
delinquent/manly uke:
http://www.mangago.me/home/mangalist/434510/
manly/strong uke:
http://www.mangago.me/home/mangalist/511652/
tough / manly uke:
https://www.mangago.me/home/mangalist/1735520/
note:
support the creators if possible, you can earn free coins completing surveys or playing games on official manga websites, f.ex. lezhin, tappytoons, etc.!
raws and official websites will be updated (when i start reading religiously again)!