Well, I've been dating my girlfriend for a little over 5 months now, 6 technically but who wants to be technical? Anyway, I always thought things were going GREAT, but up until a month ago I could feel her slipping. We talked about it briefly and I figured maybe I'd been misunderstanding everything, or mistaking the signs into something more serious. Tpward the beginning of our relationship, this guy started texting her and trying things with her, but she told him she was with me and he didn't back off. So they stopped texting after one big fight. But JUST recently, he started talking to her again and he's still trying things with her. 2 days ago, he told her he loves her and that they should say goodbye now because he won't be back from the army until October (he just left today). My girlfriend told him to stop saying it because she was with me, but he didn't stop and now they're going to start writing each other while he's away. She tells me all the time that she doesn't like him and that there are no more feelings for him, and I believe her. I've just been very, very worried about losing her because I love her so much. There's much more to this story, but I figured if anyone wanted to know, they could ask for details. I wouldn't want to bore you. I'm just curious, from that (or optionally more details), what should I be concerned about? Is there something I need to do or work on? I really need help and any advice is welcome.

Her words, and actions don't match.

She tells me all the time that she doesn't like him and that there are no more feelings for him, and I believe her
Don't you think there must be some feelings to be texting, and emailing, and now writing. My biggest point, she knows he wants more, but is okay being with you, and leading him on.

Not my idea of a healthy relationship, and sorry, I doubt I would sit and let it go on.

Just ain't that much love in the world. She would be out of here without discussion.

Don't worry. If she really does love you back, then the other guy has nothing on you. Just really think about the relationship before you continue it. If you feel uncomfortable, then really talk to your girlfriend about it. I bet she's very lucky!

Tal hit the nail on the head.

If she did not have feelings, or did not like this other person. Why continue to stay in touch? Why continue to write to each other. Etc...

RED FLAG RED FLAG RED FLAG ALERT.

Ok a few months ago I had this guy texting me. He liked me, I didn't like him. But he would usually text during work time so I didn't mind him texting as it made working easier. (I wasn't as bored)

I showed my boyfriend all the text and he didn't care. Then the guy started saying leav your boyfriend and come out with me.. saying he would get his 'boys' over to deal with my boyfriend. This anoyed my boyfriend so I told the guy to stop talking like that or he would have to stop messaging me full stop.

He stopped. Then a month later he started again. My boyfriend was getting really anoyed with him so I decided to tell him not to message me again.

If she is showing you these text then she seems to not want to hide anything. She may like me just like the attention. Have a talk to her and tell her how you feel.
If he gets worse in the letters he sends then talk to her again. Tell her you don't think its right that she lets him talk to her like that... See how she responds.

Yeah. I would suggest you have a little chat with her. Women like attention.Who doesn't? I don't think there's anything going on there from her side,otherwise she wouldn't have the nerve to show it to you.But yeah,give her a little more attention than you already are.. if you really love her,make her forget about the other dude. Its probably nothing.but don't let it go easy.Make it clear you don't want none of that monkey business.Why does she need to get attention somewhere else when you can get her everything a woman can want?
Set the records straight.talking peacefully helps.
Best wishes!