http://www.mangago.zone/read-manga/distopia_mikansei_na_sekai/ - It isn't exactly the same as you said but it gives the same feel.
http://www.mangago.zone/read-manga/sex_pistols/mh/v01/c003/3/ - This story in Sex Pistols, again it's not exactly the same (Sorry!)
http://www.mangago.zone/read-manga/oujisama_ni_narenai/ Sorry I couldn't find more
http://www.mangago.zone/read-manga/yumemiru_otokonoko/
http://www.mangago.zone/read-manga/aishuu/
http://www.mangago.zone/read-manga/empty_heart/
The last two are similar to what you wanted but it's not exact, sorry ;;
Can someone please suggest me a manga where the following happens?
The uke is in love with the seme so he confesses. But, being best friends or good friends or just friends, either the seme rejects him or the uke says that he does not expect anything from the seme, so its fine. The seme starts becoming self conscious around the uke, but the uke's being all nonchalant about the whole thing. And this really, really begins to bother the seme. And then, either of the two happen:
1)the seme begins to feel jealous when the uke starts getting close to another guy/girl whom the uke may or may not have known before (I'm not picky) , and finally realizes his feelings
2)or the seme, after a lot of drama (doesn't matter what sort of drama it is), finally realizes his feeling for the uke.