How do you know when curiosity has become a case of a bi-sexuality?

[PennyLaine]

If a guy has experimented with another guy one time sexual. He received oral but did not really like it - was too nervous. But then said he would like to give one time.

He is in his late 40's and experimented once a few years ago and has only dated women.

Is that just being curious? Or could he be bisexual??

Thanks!