I'm not sure it's very much about "letting loose" in a huge way. But his Firsts, hero worship, the fact that it wasn't in a lab he would have gotten some physical contact/lost his virginity... Hmmm. *_* -- I mean. *ponders. yes. no starry dreamy eyes here.*

Zack does ping me as naturally good at that kind of stuff. I don't think all the members of the ot4 are as totally jealousy-impaired as he is -- Aeris, perhaps, though she goes looking less, but Seph is secretly possessive and Cloud has a fear of rejection/abandonment so likely they'd be way less relaxed at the idea that Zack might go and love elsewhere, since they'd be scared he might not come back.