How do you know if a partner is narcissistic or plain insecure.

My partner tries to copy me a lot without me knowing. If I try some new product,he will try to use it without my knowing. He tries to be critical about the things I haven't done. He tries to check up on what I'm doing , but with some random reasoning.

I used to not think much of it and give him the benefit of doubt. He never gives me any praise but only tries to overdo what I did.It is like he is in some kind of competition with me. He won't say anything supportive if I am going through a bad patch but may try to do some housework or bring me food.

I'm totally confused.Is he a narcissist and how do I find out??