Responses
http://www.mangago.me/read-manga/higouhou_junai/ i think this fits the description
Hua Hua You Long.
Seme isn't aware his love towards uke.
Uke is in love with him.
Seme has past lover
Any manga where the seme is totally in love with uke but doesn't realize it because...well, he just doesn't. Seme can be straight-turned-gay,bisexual or just simply gay. The uke loves the seme but never dares to confess. It'd be awesome if some third character comes and becomes close to the uke which results in jealousy from the seme's side, and the seme finally realizes his feelings. The third character's presence isn't necessary, though. Manly ukes, please. Or at least ukes with a detectable backbone.
Thanks in advance!