And the situation is this: you are a girl, he is a guy, she is your girlfriend, and all of you, together form the so-called "love triangle". In which the whole "sin" is hidden only for two people - you and him, her favorite boyfriend. If you go in a logical way, then your friend is just a "victim" of the circumstances, in the full sense of the word. But, whatever it was, and whatever opinions are lamenting the situation, we must live on, and not just live, but also (maybe even more than once) look into the eyes of our girlfriend. What can I say when you are with her, maybe even best friends. That's why it's necessary to do something. So, you are tormented by conscience, well, maybe not at all. Of course, it's even worse if you have feelings and want to be with this guy. Whatever it is, you will still be echoing the same question, which, like a "splinter", sat in your head (and maybe deep in your heart) and does not want to get out of there: "What should I do if I slept with the boyfriend's girlfriend? ".
Self-interest.
So, first of all you need to understand yourself and answer for yourself the following questions: "Why did you sleep with him? "" What did you want to prove or say to yourself? "," Do you like this guy and do you want to continue to deal with him (and it is desirable to find out what)? ". And the last and most important question for you will be how much you value your friendship with the one with whose boyfriend you had sex. The answer to the last question will become the main argument in your further actions. After all, if a girlfriend finds out about what you did, there is a good chance that you will not remain friends. And anyway, if you went to such a desperate step, did you consider your relationship with her friendship?
Of course, in this situation there is also "the other side of the coin". You, along with him, can keep everything in secret, for the benefit of this very friendship (you mean, yours with her). But here there are minuses. The fact that you slept with a girlfriend's boyfriend, sooner or later, will start chasing you and moral pressure on your nerves. Well, and again, tell yourself, why does your girlfriend have a guy who is able to sleep with anyone, completely disregarding such human values as "friendship", "loyalty", "love"? In a word, you really broke firewood. Therefore, if you are not ready to live with this "stone on your soul," the best way for you (and indeed for both of you), of course, will be a frank confession. Although it is worth remembering that in life there are different situations and therefore sometimes you can just postpone this conversation with a girlfriend for better times. For example, your girlfriend herself parted with this guy.
What to do?
So, out of this situation, at least two outlets and, as it sarcastically did not sound, one spare. And they sound like this: say as it is, and try to explain why you slept with him, keep this secret "behind the seven locks." Or just wait for your girlfriend to part with this guy and maybe even in any way to help her with this. Decide, of course, how to act, only you. The only thing is remember that any untruth can always become a reality. So sometimes it's better to tell the truth right away, no matter how bitter it is. And it's best to do it yourself than when a girlfriend finds out from someone else.
And if love?
But everything is much worse, if you slept with a friend's boyfriend because of your feelings for him. What to do in this case? First of all you need to talk to the guy and find out what plans he is trying to do towards you and his next actions. Only after that you need to continue this conversation, only with your girlfriend. Admit it to your feelings, and if she is your real friend, and you are connected much more than friendship, she, perhaps, will understand and forgive you. Whatever it was, but to hypocrite her and secretly meet behind her - this is very offensive and wrong with her. By the way, do not ask the guy to talk to the girl. There should be your personal tete-a-tete conversation, without any "third extra" there. In addition, if your girlfriend with this guy does not last long, and they have no plans for a joint happy future, such a conversation will begin much easier. Plus, as a reinsurance, you can find a decent replacement for your girlfriend in the place of this gentleman. You know her taste, so it will be much easier to please her with a guy. But you only need to do this if you are sure that it will help you to keep your friendship, and quickly forget your former friend.
If everything is not so poetic ...
Well, in case the guy himself, he also slept with you without any reciprocity, but simply for excitement or raising his masculine "I", you will have more difficult. What to do with this guy? After all, here he is not a gift, and friendship can be lost. Our advice is to tell the truth again. The very essence of the conversation is worth building on a rod called: "Your boyfriend is not right for you ...". Explain that in your place there could have been some other girl and not at all the fact that you are not alone in his list. Therefore, no matter how difficult it was, and whatever it cost, open your girlfriend's eyes to her beloved. Maybe she will not understand you right away, but it is possible that she will thank you in a while. And for a cup of tea, you'll just laugh at this ridiculous situation. After all, people are telling the truth that true friendship is tested by trials and time.
And the last thing, remember that people learn from mistakes. Therefore, in the future, simply avoid such incidents and choose for yourself free guys and certainly not boyfriends of your close friends. Remember, guys come and go, but friendship is eternal! Do not risk your friends, and if you stumble, ask for forgiveness. This is the only thing that can justify you and melt the offended heart of a friend. Good luck!