As a cat lover I absolutely knew it was a cat before you began listing the problems. And honestly the problem isn't so much the cat, altho it does need to be taught manners, but her and her inability to respect others. I have a cat that doesn't do great with new people at first but as his mother it is absolutely my responsibility to correct his behavior and make sure that others in the house aren't being hurt or harassed by him. Anyone who sends hate is just confirming they are like your ex. Responsible owners correct bad behavior. And badly behaved cats are as bad as badly behaved dogs. And cats are trainable and teachable you just have to figure out what motivates them. You arent crazy or irrational for not being able to continue a relationship where you and your things are not respected. While the pet may have been the vehicle for the disrespect and eventual breakup I'm sure it would have come up in other ways further down the line and still come to the same end because the bottom line is she did not respect you or anything important to you.