Bromance is nothing new, or even all that unusual. Even ancient peoples wrote about it in their epics and myths. The theme that was most popular was the concept of “tragic bromance,” where one bro dies an untimely death, and the other bro is dramatically changed as a result. Of course, if you have a bro, I hope he doesn’t die too soon, but if you want to become more well-read, I suggest you check out some of these examples.
The oldest known epic is the Babylonian story of Gilgamesh, who begins a quest for immortality after his bro, Enkidu, dies. Then there were Achilles and Patroclus in the Iliad. This theme keeps showing up throughout history, and is still prevalent in modern literature, film, and other popular entertainment. The tvtropes.org site has quite a few interesting examples.
The Blog Dude