While I like all of you taking my side, I still think most of don't understand the situation.
My GF isn't manipulative or selfish (at least not more selfish than what many other girls are), most of time she is very caring and lovely, and more; she gives me gifts she's great in bed, she never takes advantage of me for money or anything of the kind. But she also can be very impatient and somewhat intolerant.
She has problems. But so do I. I am far from the perfect boyfriend. I am not very sensitive or empathetic. In many cases where I should feel something I simply feel nothing. Overall I'm also quite a boring person. I admit it. I'm not exactly what you would call a catch. So I don't know whether other girls would think of me more then she does; I certainly don't think so. So I think she's somewhat right in being unhappy in the relationship and I'm the one who needs to change.
Relationships are a give-and-take. One person has to meet the other halfway to keep things going. So far I've seen several threads about this shit all more or less saying the same thing:
"She says/feels/does [thing] that makes ME feel like I'm the one responsible for everything bad that happens."
And that's not something you do to somebody you love. Period.
Everybody's got problems, it's not an excuse to sleep around or make your partner feel like a shitty one, intentionally or otherwise. In this context where - if I remember right - she KNOWS how you feel, and is doing nothing that is actively and continually filling that void and bringing you back up, then she's just as much the problem as you claim you are.
Gifts and sex and not taking monetary advantage are not get-out-of-jail-free cards. For starters, gifts are nice, but too many ruins their appeal after so long, and quality > quantity wins out the thoughtfulness of the gift, rather than the material gift itself. Two, sex varies in importance and emotional meaning from person to person, but if you two have been together as long as you have and she claims she never at any point picked up from any conversation or action or hint that you're against casual sex or open relationships, then that's a red flag. Body language and subtle clues tell all, and I am without doubt that at least a few came up in your time together thus far. She knew, or she's got the intellect of a rock. Three, NOT doing something you shouldn't do doesn't somehow make you better. "Well, my girlfriend doesn't steal my money or anything" is pointless, because
that's how it's supposed to be, you don't up and steal shit from your partner, and by not doing something she already shouldn't be doing she does not immediately become a better person.
Personally, I think she's playing you. She's got you at a point where she
fucking cheated on you in what is very likely a premeditated scenario, and you're giving her "another chance because of honesty." The fuck does she care about honesty when she cheated on her boyfriend of, what was it, over/about a year? In all that time she seriously didn't learn that you don't like cheating or casual sex with third parties when in a relationship? Do you
really buy that bullshit?
Bottom line is, she committed one of THE cardinal sins of the cardinal sins of a monogamous relationship, and you're still giving her one more chance. And then it'll be one more chance, then another, then another, then another. If I and what appears to be damn near everyone else are correct in the assertion that she's playing you like a fiddle, then this outcome is exactly what she wants, because from here on out she knows that you'll forgive cheating if she says she's really sorry and would never have done it if she knew it'd bother you.
She fucking knew, and on the chance she genuinely didn't, then she's not ready for a committed relationship.
Either way, I feel you should kick her to the curb and cope with everything where she can't bear witness to or be involved in it. If she is indeed a player, then your pain in her gain.
Is it
really worth all this trouble for someone who clearly doesn't know you as well as you may have thought, is willing to cheat on you simply because she felt "depressed" about your relationship, and who prefers to opt for impulse actions and instant gratification while not of a clear mind, simply because she's good in bed, gets you shit, and doesn't steal your material assets (yet)?
Who cares how good in bed she is or what she gets you, what kind of fucking
person is she? Sure, everyone says their SO is nice or beautiful or smart or wonderful or whatever, but how much of the truth holds up to that? I see a girl who would rather cheat on her boyfriend that talk out whatever led her to that decision in the first place; and the fact that she just went and did it rather than ask you about casual/open sex with others or say anything until AFTER the fact shows that she knew exactly what it would do to you. She only brought it up after because she couldn't have grovelled and begged for another chance until after the deed was done.
I'll say it again. From where I'm sitting, she's fucking playing you, dude, and so far you're dancing right along to her tune.
Get the fuck out of there.