It's become much more common to have a friends with benefits particularly in the 25 and under age range. I'm wondering is the OP's gf just justifying the cheating/was she really unclear or did it start sort of casual and the OP naturally assumed by a certain point things were mutually exclusive. I've seen it happen when 1 isn't particularly clear and just kinda assumes that well they'd been fooling around and at some point they figure they are bf and gf. Whatever the case OP I feel bad. There are many people as of recently finding out their friends were seeing the best friend on the side. Hope you can find what you were looking for.

That's just wrong on so many levels

If that's the way she feels, use her for the same reasons she uses you. **** her, when she's around, and focus on your own life without her, when she's not.

Your friend sucks and so does your girl

Kudos for one of the best written FML's to date.

She's gone and you 'best friend' is a dick

The good part is she told you about it somewhat early. Her guilty conscious was probably eating away at her. What you do next is up to you but your best friend isn't anymore. If he has a significant other then they should be informed of what happened, in front of him if possible so they(and you) can watch him squirm. Paybacks a bitch.

Let her know your relationship is now even more open than she thought because you are dumping that bitch.

Still a girl friend ???

weather or not she's your girlfriend is irrelevant you need to talk to your bf he went completely against guy code