Wow, that little 4-letter word comes easy for you.
"Love". It must be easy for all of you
guys to fall in love. And that other 4-letter
word "best" comes real easy too. I'm
sure that you are super supportive of your "best"
friend in everything EXCEPT for "love" affairs,
right?
When you say that your best friend was in love with
this guy for a year, do you mean it was love from afar?
Do you mean it was TOTALLY your friend and that the
guy didn't respond at all? Or do you mean that
now the guy is telling you that he never cared for her.
Pardon me for being a little suspicious, but myself
being a guy and all...
Anyway, it's up to you to make the big decisions.
There are already consequences for what you have done.
I hardly think that your best friend will be ecstatically
happy when she finds out that you've been seeing her
object of "love".