I think my GF is cheating on me ...

I know this is a bit strange, but I have no one else to turn to and search for an answer. It's about the recent relationship I'm in. I know many of you have some much more experience on this, and some of you are even married and have kids, so I thought you would know better. I tried asking this on seduction forums, but people there mocked me.

Anyway, I've met this cute girl about 6 months ago at a party. She's really, really cute: she has deep blue eyes, blonde curly hair and has the smile of an angel. I don't know what it was, but we fell in love with each other immediately.

The first few months were great: lots of sex, lots of hanging around and having fun, and I even met her parents, despite the fact I'm so afraid of meeting parents. We didn't move together, but she always stayed at my place, and it surely felt we were actually living together.

But, after a few months, we started drifting apart. She didn't spent as many nights over at my place as she did in the past, and she became more like a stranger than a lover. However, we would still meet, and when I would ask her "What did you do last night/weekend?" she would usually reply saying things like "I went over to Alexandra's place" or some other girl's name, always reassuring me that these chicks are her college mates. Even sex started being rarer and rarer, and not so enjoyable.

One day, I remember I wanted to "spy" on her by checking out her cell phone to see what texts she received and what phone calls she made. Usually, she has no problem with me playing with her phone, but now, she started yelling at me and acting like a psycho just for unlocking her phone, saying things like "Why aren't you respecting my privacy? I never check out your cell phone!"

This led me to believe she was seeing some other guy (I suspected it was her ex-boyfriend, because she once referred to him as "her greatest love".) But I couldn't find clue to confirm my suspicions on her cell phone since she didn't let me play with it, so I wanted to check her Facebook account and see if she had any messages there.

Now, I didn't have her Facebook password, but one day she logged-in her email account, and forgot to log-out. So, I thought I would go over to Facebook and reset her password and receive a password reset email in her email account, which I would use to set a new password. I also planned to delete this email when she would try to log-in on Facebook and saw her password was incorrect.

So I went over to Facebook, asked to reset the password, and indeed, I received a confirmation message saying I would receive and email with the password-reset instructions in a few minutes. Minutes passed by, but still, no email got in her inbox. But then I remembered she's using Gmail and she has the "Promotional" tab on, so I checked there. Needless to say, the email was there.

Now, why do you think the email landed in the "Promotional" tab instead of the "Inbox" one, as it should have? Do you think Google sees Facebook messages as promotional, and therefore a waste of the person's time?

Let's discuss this.