Hmmm maybe these??
http://www.mangago.me/read-manga/koimonogatari/ realistic but still not completed :(
http://www.mangago.me/read-manga/kitaru_harekake_no_ashita_yo/
http://www.mangago.me/read-manga/nanohana_boys/ not officially shounen ai more like deep friendship but it’s really good
http://www.mangago.me/read-manga/good_day_to_go_crazy/
http://www.mangago.me/read-manga/never_understand/
This one is very cute!
http://www.mangago.me/read-manga/motto_hanashi_o_shitai_no_dakedo/

Hi! Can you recommend yaoi with a deep romance (not overnight) ???? similar to Haru wo date ita or dark heaven