We really can't make the decision for you.  We are people from the internet looking at 5 lines of text.  The situation probably goes than those 5 lines of text, you know?  First you need to decide whether or not you think you can/want to continue your relationship.  Ultimately, we cannot decide that.  You are probably feeling a lot anger with her for violating your trust like that.  It would be hard to work through.

As for getting with her sister, it seems like that would serve to cause more animosity in the situation.  I would tread carefully in that area if I were you.  It might cause a lot of bad blood.

Feel free to pm or post some more detail or information, and I would be happy to help you out further!

~Shaun

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http://www.golivewire.com/forums/peer-ybbbyot-support-a.html
I didn't take you at face value, and I'm fine with what's underneath.

I agree with Shaun, who replied to your topic above.  As he is a male, I will try my best to give you a female's perspective on the situation as you are a female as well.  I know this must be a really difficult situation for you to be in right now and I'm sorry you're experiencing this.  I just want to assure you that you are not alone.  There are many people who care about you and want to help you in any way that they can.  

Like he said, you haven't given us much detail here and the situation probably has a lot more to it.  However, with the given information, I will do my best to help you in any way that I can.  Please keep in mind that I am merely giving you my own personal opinion and you are under no obligation whatsoever to listen to what I'm saying.

Personally, I don't think cheating could ever be justified.  I could only imagine how much this girl has hurt you because you obviously have very strong feelings for her.  It's unfortunate that many people experience cheating because ultimately, it leaves many people heart broken which is never a nice feeling to have.

If I were in your position, I would try my best to move on from this.  I do know that could be really difficult to do because you have such strong and intense feelings for this girl.  However, you have to keep in mind that she really hurt you and who's to say that she won't do it again?  Even if you let this slide and you continue your relationship with this girl, what if she does it again?  I don't want to see you get hurt more than you already are.

In regards to the situation with her sister, I think dating her would be a really bad decision.  Not only because it's her sister but also because you've just come out of a relationship where you cared about your partner dearly.  Give yourself some space to breathe for a little bit and allow yourself to recollect your thoughts.  A break up is never easy to deal with and this situation is already very complex.

Like Shaun said, I don't think dating her sister is such a good idea because of the animosity between the two sisters that will indeed unfold.  Honestly,  I think you should just move on from the both of them.

I know life doesn't seem to be going your way right now and I'm very sorry for that.  Life is unfair.  Life will throw you curve balls and life will knock you down.  What makes a strong person is not how hard they hit, but how hard they can get hit and keep going.  There's no where left to fall when you've reached the bottom.  Even when it feels like you've reached rock bottom, from there, there's no where to go but up.  Things will *always* get better with the right amount of positive thinking and optimism, no matter how hard that may be to do.

I really hope I've helped.  If you ever need anything at all or feel the need to discuss this further, don't hesitate to message me any time as my inbox is always open.  I'm always happy to help.

Good luck and I hope everything works out for you.

DYL

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You're like a bullet to my brain, I'm numb, can't kill my fun.
If you're good and done then thank you just the same.
I don't owe you anything.