Definition of "curious"

[fitnessjock]

This issue to me boils to a question of "what if?" The typical scenario may be a str8 man who never has any sexual attraction to other men in real life situations at the gym, bar or pool, but occasionally finds an image on the internet that peek his interest. This same man greatly admires himself but not other guys. Yet he thinks to himself WHAT IF another guy came along who fit all the narrow specific criteria who just happened to be a great looking guy very similar to himself. Who just happened to be gay and really liked him. There would be 3 possible outcomes.

1 He would realize that this is real as oppose to conjured up what if fantasy, a discovery this really isn't for him.
2 Feel some temptation, but know that many of his straight friends would frown upon this behavior if they knew, therefor resist and walk away.
3 Be aroused to the point were he goes with his urges and takes a walk on the dark side.

The question is, if a guy cannot definitively rule out scenario 3, does that make him bi-curious? Bi-sexual? Or completely straight since scenario 3 is very hypothetical?