Tada Omoukoto wa
When Hiroya, the one-sided love of Yuuki's life, finally sleeps with him after ten years of pining (and a lot of alcohol), he calls it a mistake and vows to make things right. But while they're closer in the aftermath than ever before, Yuuki is miserable knowing he's not what Hiroya wants. OR IS HE? Also features the delightful "I thought we've been going out all this time" trope. Also also features a kickass married couple who counsels them.
Samishigariya no Love Letter
One afternoon, a boy finds a chocolate tin in his bag and begins to correspond through it with a boy he's never met. Childhood friends finally start dating. (The one where the older one is oblivious and thinks they're "practicing" and the love of his life is tall and blond with piercings, and everyone is scared of him. This is the story with the end comic where their parents have been in support of their relationship since they were small and had already looked into moving the families together and planning a wedding.) Ten years after his five-year-old friend proposes, a man has to decide if he wants to honor the promise that they'd one day marry. I skip this one on reread.
Asatte ni Kiss