Help me find these yaoi mangas!!

So I have these few mangas that I wanted to find since a lot of days ago and it's irritating me so. I know you guys had these feelings so pleaseee, help a fellow fujoshi out.
1. The story contains three main people. The person who was always in the library, his "father," and his schoolmate. So it starts with schoolmate (sm-kun) bugging library-kun and stuff like that. Insert cliche things that made them closer then sm-kun realized library-kun was waiting for someone who turns out to be his father. Sm-kun caught a glimps of the father and it seemed to him that they didn't look father-son at all! Which is true, considering the so called father made library-kun a subsitute of his dead sister (to have h-stuff and all.) Skip, skip, turns out he really wasn't his father and library-kun's father was sm-kun's (and they already did it bec library-kun wanted father to be jealous.) Skip, there was a fire, "father" died, library-kun was unconcious and suspected to have amnesia. Last scene was sm-kun in love with library-kun but suspected him to have amnesia and left him to fulfill a promise he promised with library-kun supposedly.
2. I forgot most things of this one though I remember a scene. Seme sensei x uke student. Sensei was teaching math for his students which his lover was in this class. He realized lover wasn't there. Few minutes into class he made a class do an seat activity. Lover was under desk all along. Lover was devious I think. He bj the sensei tho sensei was obliging. At the end they did while sensei was standing up and lover was underneath the desk showing his bottom hole to him in class.
3. Also seme sensei x uke student. Student suddenly confessed to sensei. Sensei was hesitant but he agreed somehow but he warned that there are adult ways that adult people does for fun (h-stuff ofc.) Skip, sensei cheated with a girl when he was drunk. Student found out when he was at sensei's house. They were about to do but then they knocked over a trash bin which an used condom fell. Undoubtly, student knew they didn't do it recently. They fought. They talk for awhile. Sensei was guilty. Suddenlt student was the one who apologized and said it was okay for him to sleep with other people. Sensei corrected him. Blah blah happy ending!

Pleaseee help me out here