You mean the talk Cloud says to Sephiroth of how she will never laugh, cry or feel pain any more? That's the same type of feelings anybody would feel when someone they like died. I know someone who died recently and I felt the same questions Cloud did, but I was not in love with that person. Heck when one of my fish died I was upset about how it would never swim around anymore. (I was going to say more things I'd miss about the fish, but they are rather dull animals.)

Also nobody said the triangle had to be perfect. It could be something like this.



But if we are talking the love triangle literally that means that Tifa and Aeris loved each other too and while I wished that was true (believe me I do), sadly for every slashfic writer it's not.