My girlfriend saw my ex-boyfriend for three years and sent me away at the hotel!

Your girlfriend may have a heavy heart and an old relationship is hard to break. I suggest you communicate well with your girlfriend. After all, the past feelings are gone. If you are always immersed in it, it is not good for your current emotional life and help her out of her emotional predicament. If she doesn't want to, it means that she may still love her ex-boyfriend, so break up.