Responses
https://www.mangago.me/read-manga/love_your_love_enemy/
might be wrong but I believe this counts, been awhile
Alpha buddy
Boundary of delusion
Person 1 has a crush on Person 2,
Person 3 comes in and starts competing with person 1 for person 2.
And in the end Person 1 and Person 3 get together instead.
The only one I know that's like this is Protect your Purity