Stop it immediately. Your feelings for this guy, plus your son being allowed to call him dad is going to really confuse your son. I know your feelings for the guy might make you reluctant to ask him to stop allowing your son to call him dad or even to correct your son in front of him, but your son needs a better example of fatherhood than a "love triangle" situation.
If you still like her or want to be her friend, then yes.
Tell your girlfriend the truth!
A girl might say: Hey girlfriend! or: whats up sister?
If you are serious about the relationship and like your girlfriend more than the friend, then ignore the feelings and get over it. If you like the friend more than your girlfriend and the friend likes you, then possibly end the relationship and start a new one with your "friend". Don't be scared to break up with your girlfriend and end up cheating on her. Just remember, if you like your girlfriend more, ignore the feelings and move on; and if you like the friend more and the friend likes you, end the relationship.
Well, it depends on if you like your girlfriend, if your best friend is a girl, then trust me she should like you back.
Just as a friend
Well you have to ask your friend what kind of taste does he like......
Forget him
Grow up, please. If you like your best friend, you don't love your girlfriend. You girlfriend cheating on you is not reason or justification for you to do it back. You didn't like being cheated on, did you? So why would you do it back? You obviously forgave her & tolerated it. If you can't, LEAVE YOUR GIRLFRIEND. Do not go out with your best friend if you're not single.
If you like a guy and he has a girlfriend then you should back off and only try and be his friend.
I say if you still talk to her call her your friend but if you to are ok with long distance relashionships the your girlfriend
start thinking of her as a friend and not as a ex girlfriend. treat her as if she is your friend and try to get comfortable around her as a friend.