Cloud's bond to Aerith is due to the high levels of Mako (Lifestream) in him.
They do, however, meet in the Dissidia series, where they both appear as allies and warriors of Cosmos. Since Squall is from Final Fantasy VIII, while Cloud's is Final Fantasy VII. As Squall and Cloud are from different Final Fantasy series, they have never met in canon. Out of the two of them, I think it's clear who. Sephiroth lost his friends, and went mad after mistaking his origins.and then he wanted to kill off the entire planet and poison the Lifestream.
