Before Zoey left sure, or at least Zoey would. We know earlier Tremolo felt love (or at least something like it) for Zoey. However how I interpret Zoey during the interlude, for her it was just lust, fun and friendship. Not love involved (other than the love you feel for just a friend) at all. That's also why I don't count it as a relationship before she left.
Well i think thats obviously wrong.
They both had feelings for each other but werent aware of it or to inexperienced/confused to really see it how it is.
Do you think Zoey did fall magically in love with him while being away? No, she just became aware of it. Thats the theme of the two, they were both too young/confused to be aware enough of their feelings.
And im pretty sure 99% of the readers here would consider Zoey doing stuff with another guy back than as cheating.
You drew comparisions to Jill or Quinn in another post but these are different. In quinn's case its outright stated by her that shes not looking for a relationship and very clear about it.
In Jill's case its the other way around and its the MC who states some non-commitment in the beginning of their dating (Jill accepting that is kinda unrealistic and just for avn reasons tho lol).
But you may realize its always at least somewhat mentioned what kind of relationship this is, same with Sage and Lily for example who are very adamant and specific that these are "only" fwb relationships at the points in time when it happened.
Something like that never happened with Zoey, they just didnt talked about it at all because they were two dumb teenagers