To tell or not to tell about my sister's infidelity?

my sister's boyfriend moved away almost 2 years ago they still consider themselves boyfriend and girlfriend. They see each other every summer, he comes and visits at the beginning of the summer and she goes there at the end of the summer, they love each...

other a lot, but a few days ago my sister made out with someone else. She said she had no control, and she told me not to tell my mom or her boyfriend, but she said she will tell him this summer in person, what do I do???

Do not tell this story anybody, and do not blame your sister at all! Let your sister to solve this issue as she can or wants. But do learn that; long-distance relationship is not exactly the same as a close relationship. Being alone for longer time can make anybody to be so horny that she/he may loose the self-control, and that is not so big deal as you think about it now. Be careful: you also may be in similar situation.

I think what your sister did was wrong- and she has no excuse just because she couldn't control herself! However, it's her business and SHE needs to fix this problem. Let her make her own mistakes, and you can learn from them without interfering in her relationship. She'll make her own decisions, and maybe it will work out- maybe it won't...either way it's her life.

Hunny, honestly this is between your sister and friend.
Let the pieces fall were they may and just don't say anything keep her trust and stay out of this.

What she did was wrong but i've done it too, and I would have never forgave my sister if she did that.