Anyway, what would you do if your gf said that she's gonna have lunch with a guy friend.
I don't let this 5hit bother me. Why? Because 97% of the population are AFCs. I'm more interesting, fun and confident than them. The woman also knows that I will ditch her a55 if she misbehaves.
You're going to get competition no matter how hot or ugly your woman is. Men love pu55y and they'll try to woo your woman with what society says works: dinner, compliments, looking for pity, and talking about how intelligent they are. These things do NOT spark a woman's emotions.
Now, what are YOU doing to spark her emotions? Being funny, spontaneous, confident, sexual, and even occasionally pissed off will keep her emotions fluctuating on a regular basis. If you're just sitting around every night watching movies with her and then having missionary sex to get yourself off, she's going to find dinner with some other dude more exciting than spending time doing the same old boring things she's been doing with you. Why? Because it's different, and different gives her emotional fluctuation.
When a woman is attracted to her bf, dinner with some other dude is nice, but she'll be happy to come back to the world of excitement she has with you - or what she SHOULD have with you.
My gf accidentally left herself logged into fb on my computer, so I looked at some of the messages she had from the time we started dating. The first one I saw was one of her male fb friends telling her she looks sexy. Her response? "Thanks, my bf things so too." The dude got jealous and gave her 5hit for mentioning little old me.
A second message had one of the guys asking "how come we never ended up in a relationship?" Her response to him was "because I like older guys".
Should I be worried about any of this stuff? No, at least not right now. If her behavior takes a sudden turn, then I'll know she's zeroing in on a new target and it's time to dump her. Until then, there's no point in worrying about dudes trying to steal my gf (and I honestly can't blame them, she's hot!) It's going to happen and it's completely out of my control.
You're best bet is to learn to live with it.