Is it time to end my LDR?

[book_worm]

My SO and I have been together for 2 1/2 years now. And most of that time has been LDR. We spend the school year 250 miles apart, but then we are together for the summer and any breaks I have. Recently I have been questioning if he is being completely honest with me. Tonight I got really, really frustrated and did something really stupid.....I hacked into his Facebook and read his messages. Which I know I should have never done, but what I found was awful. I found messages from a girl saying she wanted to cuddle, and making plans for him to go over and spend the night, which is sounds like he has done, or atleast planned to do. This girl has a SO as well which my SO brought up frequently, but never did his concern stem from being with me. He hesitated in the conversation to make plans last night to go to her house, and she fought with him why. He said it wasn't a good idea but eventually said he would. I called him out on this. He says that his brother was messing with his Facebook, and he doesn't even know who she is which is why he deleted her (which he actually did before I confronted him). I really don't know what to do. I try to talk to my friends but they don't understand LDRs to begin with. I know this wouldn't be happening if I was home, but that doesn't make it okay. I never, ever imagined him doing anything behind my back like this. I know him and this girl haven't kissed, or had sex, but to me cuddling is a huge violation of what we have.
When I brought up the conversation to him he got mad at me for snooping....which I do realize is wrong. But if it really was his brother why blow up and scream at me? Deep down I'm fairly convinced it was him talking to her.
I'm looking for advice from people that understand the complications of being in an LDR. Am I overreacting? Do I trust it was his brother? Or is it time to end this relationship and move on?
Thanks for the help!

[Miramaid]

you are not overreacting and i am sure it was him. I had a very similar story and unfortunately let it go...The results were and are not good. He is now very secretive about his passwords and eventually he deleted ME from his FB. Claiming that it was my fault coz I snooped. IF i could turn it all back in time I would have left or make him prove to you that it will never happen again (you decide how he can prove it. To me it would be leaving his FB accessible to you)

[Minerva]

You snooped and he's sneaking around with another girl. There's no trust on either side. If you want to make this work, you BOTH need to stop what you're doing. You need to have a serious talk. If he won't come clean about messing around with another girl ("someone else was using with my account" is the oldest excuse on the internet), I don't know how you can go forward. You need absolute honesty to have trust. And without trust, you have a relationship speeding to an end.

So you need to promise him you'll never violate his privacy again (and don't!), and he needs to tell you the truth about the other girl. Keep in mind, however, if he's honest, you might not like what he has to say. Be prepared for that. It'll hurt. But his being honest is the only way you can start to trust him again. Because getting caught and then lying about it destroys trust even faster than just getting caught and telling the truth.

It can be rebuilt, but you both have to want it, you both have to be completely honest, and it's going to be tough for a while. But if you love each other, it can be resolved.

Good luck.

Edit: sorry, just reread your post, I kind of missed the point. Are you overreacting? No, not if you think he's lying. Should you trust him, should you end it? That's really only something you can answer. If you think he's lying, then he's cheating and lying about cheating (and yeah, I think flirting and cuddling with another person is cheating). I'm not you, I don't know him, so I can't tell you if you should believe him or not. But like I said, "someone else used my account" is an old, lame excuse. And I can't tell you to end it, because if you love each other and both want it to work, you can do it. But if you don't trust him to the point of hacking into his personal account... that's not good. You know how wrong it was, but you did it anyway, which means either your morals are not too strong, or he's given you so many reasons and red flags that you got desperate. To me, it sounds like the second.

Trust is so important in any relationship, but even more so in an LDR. Once that's gone, everything else will start to go too. So I guess you need to figure out how much you love him and how much you trust him, and your answer will be there.