Have you tried Void by Zariya? http://www.mangago.me/read-manga/void_zariya_ranmaru/
Oh, It have some rape-scene, so if you feel uncomfortable with that, try something else.
I know you said that you prefer the one with Happy ending but in case you were searching for some tragic story try this one
http://www.mangago.me/read-manga/kimi_no_naka_ni/
Wait, actually maybe you already read that xD
+1 The one Fujoshi001995 recommended, my favorite.
Just be patient with the angst on the beginning. It's complicated true deep love with awesome end.
Substitutes ukes ! Here you go :
http://www.mangago.me/home/mangalist/198354/
Its similar
http://m.mangahere.co/manga/junjou_romantica/
Any yaoi with seme is broken hearted and the uke act as a replacement for the seme's lover... Things happen and although the uke is just a replacement, the seme finally fall in love with the uke. Preferably something with happy ending. Thank you.