I consider myself a straight male, but...

The idea of a threesome involving another (attractive) male and a a girl , really turns me on , and not just in a "fuck yeah I'm having a threesome" kind of way.It's in a way that I would get really involved in pleasing and playing with both the guy and the girl, and doing anything to both of them. But the idea of being with a guy alone doesn't turn me on at all , I've never been in either situation so I can't confirm id actually enjoy either , but really I just wondered if there was any other guys who consider themselves straight until they put themselves in a certain fantasy situation?