Well yeah, Choco strawberry vanilla.
http://www.mangago.zone/read-manga/choco_strawberry_vanilla/
But they don't "realise". The relationship is strange. It's a perfect triangle imo tho two of them love each other platonically, but no less intensely , tho many people dislike one character but i don't, he's different from us, so is his friend. Psychological genre to be kept in mind. Gahhh I can't explain. Just read it it's an awesome manga!
And yes... This. This is one-sided "love" till now tho.
http://www.mangago.zone/read-manga/a_man_like_you/
And this manga as well, they don't "realise", they already love each other, but they also love the other. Perfect love triangle.
http://www.mangago.zone/read-manga/ai_to_makoto_moriyo/
Any BL manga where two guys are fighting over one guy until they realize they’re in love with each other?