I'm at volume 13. The couple is solid, there's no real love triangle. Other love interests do pop up, but they're more third wheeling than triangulating if you know what I mean by that. There's only one that I would call a serious contender because they were very good partner material (I liked them), but by then the couple was together and it was very clear that they would be rejected. Honestly it's the weakest part of the story so far. There's plenty of emotions beyond crushes in this story, it's wonderful.