I have a problem with my girlfriend's guy friend. Any advice?

I think it is disrespectful on both of their parts. If he was really a friend to her he would want to value her relationship with you. And if she really was concerned about how you feel she would confront him in an appropriate way. Unfortunately girls do like attention and maybe she is just enjoying the attention from him, but if it is hurting you she should see that and try to ease the stress for you. Also, try doing something really special for her to remind her of how much she loves you. Also, try to find out why she needs this attention from him. It sounds like you guys have a solid relationship and you have done the right thing by telling her how you feel. Just make sure you tell her how it hurts you and try not to come down on her and make her feel defensive cause that might make her run to him.

She does sound like she might becoming emotionally attached to him. Honesty is good. I am glad you talked about it with her. She might like the attention of someone new. I know that hurts. Have you tried talking to the guy about his intentions? It's really disrespectful of him to want to carry on and flirt with her. She is noticing he is flirting then she should know it is really bothering you. Don't keep confronting her start asking him. Good Luck!

I've gone through something similar. A sign of your girlfriend becoming attached to another really takes it's toll on you. I agree with the other answerer about the confronting the other guy about it. You told your girlfriend how you feel and it's getting somewhat better, so just let her know that it makes you insecure when she secretly talks to this guy. The guy to me seems as if he wants her more than a friend. Late night IMing and texting aren't what friends really do, especially when their significant other is around.

Just keep letting her know where you are coming from. You may even explain to her in the words you used in your question, about how you trust her but you don't want her to lose interest in you. If her love is what you describe, then she should have no problem in trying to make you feel more comfortable by adapting to both your wants. Remember to also contact this other guy too, and let him know that you and your girlfriend are in a serious relationship. He should respect you enough to not flirt with your girlfriend, and not try to be more than friends. If all else fails, all three of you have to sit down and talk about what's going on and get to the bottom of the whole story. I'm sure as long as you tell your girlfriend how you really feel she will understand.