Clarification/Follow-up by jelly on 11/14/06 9:25 am:
Thank you for the advice. I am not sure what you mean when you say that I should consider whether I should encourage inconstancy.

Clarification/Follow-up by jelly on 11/14/06 9:25 am:
Thank you for the advice. I am not sure what you mean when you say that I should consider whether I should encourage inconstancy.

Clarification/Follow-up by jelly on 11/14/06 9:25 am:
Thank you for the advice. I am not sure what you mean when you say that I should consider whether I should encourage inconstancy.

Clarification/Follow-up by Jim.McGinness on 11/14/06 1:08 pm:
It possible to be entirely selfish and just do what makes you feel good, currently, without concern for either the future or for the effects of your actions on the broader environment.

If the fellow in question is already going out with your best friend, you could still go after him, but one of the effects would be to encourage him to switch attachments more readily. There's a whole system of signals males and females can use to indicate their interest and availability. If the guy were truly attached to your friend, it's less likely that you'd be thinking about going out with him. If he was just scouting around, with no current attachment that you knew about, he'd certainly be fair game. Since there's already some mutual inclination between him and your friend, it might be best to let them try each other out -- without outside temptations -- for a while -- before you try to get your turn.