It really doesn't sound like it's you that needs to change. It sounds like he's inadequate in maintaining a healthy relationship. Cancellation of plans frequently, it's not encouraging to read about. It's not displaying commitment to the relationship. And now it's eating away at you, leaving you questioning if it's you and asking yourself how you can change. No need to excuse this under the label of agoraphobia, it's up to him to work through this to maintain his relationship with you. Leave you feeling special instead of flawed.