Question about Employer-Employee confidentiality?

Hello. I am an assistant manager for a local gym in my area. My general manager quit about 4 months ago and we hired a new general manager. I trained her for about 2 months. She has never done the job right. I have assumed most of her responsibilities while she spends most of her days working out while on the job. A member complained to the owner of the gym. The owner came to me and asked me about it. I told him the truth. She is lazy and abuses her authority. She calls off all the time leaving me to have to come in and fill in on my off days. I thought he would fire her. Instead he told her exactly what I said and even told her I was the one who said it! She has been now adding extra duties to my job, making me fulfill more of her duties and has had an overall sour attitude towards me. Is it legal for the owner to tell her what I said? I was just answering honestly. I don't understand why I have to get punished for doing my job and being honest. I have worked there for 5 years! Her 4 months.