It pisses me off when an author moves on to a side couple without giving us closure from the original one. In the first place I don't even like side couples. They may be nice or have a nice story but I didn't go there to read about them. And now I get to see them have sex but not the couple I actually care about? Annoying.
I feel the exact same. If the side couple can't catch my attention in the first few pages, then I end up just skipping it. Very rarely have I been interested in the side-couple's story. Literally can count on one hand and I've read literally hundreds of bl manga.
It pisses me off when an author moves on to a side couple without giving us closure from the original one. In the first place I don't even like side couples. They may be nice or have a nice story but I didn't go there to read about them. And now I get to see them have sex but not the couple I actually care about? Annoying.