There is no possible way you can tell your friend without ruining your friendship.
(Alternative):
Depending upon your best friend's personality and beliefs, it may very well be impossible. It also depends upon the intimacy of your relationship with your best friend's boyfriend. The more intimate the relationship you had with her boyfriend, the more damage your friendship may take.
You may be able to minimize the amount of damage by passing it off as a casual relationship (i.e. "just friends"), however this could backfire - especially if saying such a thing is a lie and this is found out.
If your best friend has a forgiving personality, then the best way would be to be honest and apologetic. Most likely your best friend will still be hurt and will still be angry at you, but in time your relationship may heal.
Mind you, if your intention is to still be able to date your best friend's boyfriend even after admitting this to your best friend, there is very little chance of your relationship surviving. Your best friend will probably see this as you trying to steal her boyfriend.
Of course, there are always less... ethical... methods to get what you want, but I (along with most upstanding people) can not advocate this course of action.
Slap him
A friend you have sex with but are not dating. Not a boyfriend or girlfriend, just a friend with benefits.
I think you should ditch your best friend and replace her with another person who won't betray your trust by dating your boyfriend. That's what you should do.
AnswerYes! That is so wrong unless you break up with your boyfriend and your friend's boyfriend breaks up with her first. Even then, it is a mean thing to do to a friend since you'd be dating her ex.Some would even argue dating a friend's ex is a mean thing to, even if you never participated in cheating.
If you and your boyfriend are still dating and have not split up then this friend of yours is not a true friend to you and you should consider her a toxic friend and walk away from her. If you and your boyfriend broke up and she dated him and obviously didn't tell you it is probably because she didn't want to hurt you. In this case talk with her and tell her that she should have been honest with you, but you should still remain friends.
Usually if she's prettier than you.
Your friend is just trying to make you jealous just ignore them.
it only means you like your friend ex boyfriend and that wrong
you should try asking your boyfriend to talk to him
well, if he's dating your ugly friend, you must not be all that attractive....get a make over, or make him jealous
She isn't a very good friend, ex boyfriends are off limits!
your nephew would be the stepfather or boyfriend of your friends mother