He Pigged Out On Food
It sounds childish to break a relationship because of different attitudes toward food, but eating together happens at least once a day, at most thrice, so it’s as good a chance to find fault against a person as anything you do together. If you chew food and the person feet away can hear your chomping sounds, or if you’re a hedonistic fatty-food eater while she is a self-professed vegan, either you dump your diet or prepare to be dumped by you-know-who.
Living with someone involves sharing a part of your life and exploring the world together. It won’t hurt to see things from her perspective once in a while.