Most Helpful Girl
Couple of things. Your girlfriend shouldn't be slapping you. Second, put yourself in her shoes for just a teensy second... now she's the one seeing an ex of hers after a long time and going over to his house and hanging out with him and hugging him, do you still feel so chill. You're right in that you should be able to hang out with whomever you want... until that is, it comes down to exes or anyone you had sex with no matter how many years have passed. We all know shiz happens, and no that doesn't mean you're cheating on her, but shiz happens because emotions/chemistry whatever still linger in the air sometimes in past relationships which often makes new relationships seriously nervous even if you are a good guy or she is a good girl not doing anything but actually hanging out. Aside from the slapping, just give respect to new gf's feelings on this. She's going to have to trust you, but just know that its always a bit different when it comes to exes and relationships, friendships or not.