You know what's funny about this... it's that it's true, but at the same time, you need to take this a step further.
Aerith in OG asks them both, they deny it and she pursues Cloud and they fall in love. Tifa "watches" this happen according to the Ultimania.
But let's pretend you want to deny that happened...
Well, in Remake, Aerith knows everything. She asks only to go through the motions. She pursues Cloud regardless... Think about it.. Why would she do this?
Now, if it were true that Cloud and Tifa were canonically a couple in OG; why would the Whispers or Aerith care about any of this? Why would she need to go through the motions at all? Why wouldn't she just leave Cloud alone -- especially if she loves Zack, supposedly?
Notice how none of it makes any sense?
I hate her. Don't want someone as her as my BF.
She knows Tifa loves cloud and is flirting with him non stop. she is such a red flag.