Does Zack love cloud

No. Zack likes to flirt, but he was never in love with Tifa. The only girl he ever loved was Aerith. It's stated by SE that Aerith became irreplacable to him, and she's the only girl he ever wrote home about. At the end of CC, he fights desperately to return to her, but...for a certain reason, is unable to. Play CC for more details(even though it's obvious what I'm talking about if you've played the original FFVII).