This question already has an answer here:
I am a new manager (junior/assistant head of department), promoted one year ago, and I have always had five star performance ratings as well as been recently named best employee of the company. On the surface, I have little or no reason to believe that I have had performance issues.
During the recent performance review, however, my boss told me that someone else would soon come and help look over my team. In fact, this person is a friend of the CEO with little technical experience in my function but has been fast-tracked. De facto, I also feel like he is becoming more and more our new boss, giving me and my team commands. During the appraisal, I did feel a bit uncomfortable and asked my boss:"Is there any negative feedback about my performance? Anything I could improve?" And he said:"Absolutely not, you are doing a great job and you should continue like that!" In that instant, it reassured me, but now 4 months have passed and I feel more and more like I am being cornered, stripped of my responsibilities, and being excluded from nearly all decision-making. This was my hunch back then, and it is turning into reality. My boss has more meetings with the new guy, and the new guy has independent meetings with the others in my team.
The doubts and anxiety about this are increasing every day and I feel quite betrayed about this. I also think my actual performance is dropping due to this, as I am constantly focusing about the team, about what to do to improve the team and prove myself, and confused about my tasks which are increasingly technical. All in all, I have reached the point where I cannot take it anymore and need to talk about this with my boss.
I want to develop my path as a manager and grow to a senior level leader, so I need to learn what are my mistakes and what I need to change, etc. How can I confront my boss about this?
Note that this is part of a larger question, but I am breaking it down to more specific questions following the request by members who dislike too generic questions. I also hope this makes the question and answer more relevant to a larger audience.