Manga with older seme like at a very old age

?
http://www.mangago.me/read-manga/how_sweet_is_a_sugar_daddy/?av=1
http://www.mangago.me/read-manga/yuki_to_matsu/
http://www.mangago.me/read-manga/because_of_you/
http://www.mangago.me/read-manga/kirei_ni_shiteyo/
http://www.mangago.me/read-manga/oita_ga_sugiru_wa_koneko_chan/

http://www.mangago.me/home/mangalist/607063/

Tnx

do you mean, like semes in their 40s or so or a big age gap?

Semes in their 40s