I understand how you must be feeling. Believe me rejection is one of the worst feeling to have and that after 15 yrs. of togetherness.
Bitter fact is, he is not interested in you any more. Try to accept the fact. Reasons can be many. To comment upon reasons I need more details. If you find a new job of same position or little lower position (if you can afford and accept), change your job. Probably he might be wanting the same and that could be one of the reason of his misbehavior. Your inability to do so may bring you more suffering.