Problems with boyfriend

So I have been seeing this really nice guy, we met on tinder and started going out and we have been together for more than a year. The problem is that he is completely out and proud and accepted and I am totally in the closet. The other day he opened a topic again and said he was really getting tired of all the hiding and pretending we are friends and so on and asked me if I will finally come out. And there is the problem- although I want to be open about our relationship I know how much it will cost me- all my friends, my family and that thought is so hard to bare. I don't know what to do, my boyfriend says that being with me while in the closet makes him feel like I am ashamed of our relationship and that's not true, I am just having a hard time because I don't know what to do and how to handle this. Any advice?