Sharing Facebook passwords? I am SO confused!?

[M]

Last week my boyfriend gave me his Facebook password because he believes there is no such thing as privacy in a relationship, and he felt that by giving me this privilege I would feel special. He also stated that he didn’t want my password, but rather just wanted me to feel special about having access to his. I was aware that he used to share his password with his female best friends as well, so I told him, I didn’t really see this as a privilege because he seems relatively open about Facebook password. He got upset, and was disappointed that I didn’t indeed feel special, but later got over it. Well, I have his password, but I have not logged in. I haven’t logged in because 1) he doesn’t have my password which makes things seem unequal 2) because I’m afraid I’ll see something I won’t like, and might end up misconstruing it. All of this is giving me a headache, and I seriously cannot decide whether sharing passwords is healthy for a relationship or not. I want to discuss this with him but don’t know what to say or how to go about this situation.