i want a YAOI/SHOUNEN-AI with a slight sex... much better if they focus on love.

This is a doujinshi, but I really love this author's style. I don't know if you like Haikyuu, but this dj is really good. Good characters, very sweet plot and not to much sex. If you like it, you can read all sensei's works! http://www.mangago.me/read-manga/haikyu_dj_gunjou_no_shashin/
Then... this series! http://www.mangago.me/home/mangalist/117519/ Slight sex, a lot of romance and very precious characters.
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I love this one http://www.mangago.me/read-manga/ichi_ni_no_san/

Three of my favorites
http://www.mangago.me/read-manga/nirameba_koi/

http://www.mangago.me/read-manga/soba_ni_oitene/

http://www.mangago.me/read-manga/aitsu_no_daihonmei/

I have a few like those here - http://www.mangago.me/home/mangalist/26616/
check out my reviews for more details.