lack of intimacy, or high rate of negative energy, low self esteem and complaining over everything, asking more than giving and valuing the giving highly and mention it and use it ! guess that's my tops which repels me off without a second thought, of course other miner reasons can be solved or talked over but these upper ones are cure-less !
If it were early into the relationship, I would be gone if I caught her trying to hide her drifting, bedroom eyes while looking at men.
As for the friends with benefits, that usually does not last all that long. After over a year the there is no mystery left to discover, the, "new sex partner" thrill is gone and because there is no commitment the emotional attachment is most likely weak at best. It would be easy to walk away from her.
If it was a friends with benefits relationship? Sorry to break it to ya girlfriend but he doesn't care about you. You have no right to be upset about it. You two didn't commit to each other. You can't be surprised and you can't be upset.
FWB' s are for no strings attached sexual liaisons, for the most part. He may have felt an attachment growing on your part. Or maybe he is involved in a serious relationship , which makes him a scumbag