A girl did something very similar to this on a first date. Not out of anger but out of what she described as humor. It was jarring for me and it was really hard to shake the memory/feeling. Ultimately it did play a role in me choosing to stop seeing her, though there were other more prominent factors. In the end I would say it is an indication that he is not worth your time. But ultimately that's your choice. Forgiving him for something like that would be a huge step of trust on your part, it's hard to shake. I think you will get a good indication of his inner behavior if you tell him that it hurt you the way it did and watch his reaction carefully. If my partner was remorseful and expressed it in a genuine way I would consider forgiving them. But if they were saying sorry just to say it, I'd be over it in a second. If you feel comfortable doing so, talk to him about it, tell him how jarring that kind of thing is, make it clear what that behavior does to you, and then watch him....just say nothing and watch him. His reaction, verbal or non-verbal I think, will give you an answer. In the TV show the wire a number of characters say, "Do what you feel" and i swear thats a line I live by these days.