Boyfriend gave me his Facebook password?

[M]

My boyfriend and I have been together for 7 months, and we get along great and are both in our mid 20s. He's told me in the past that I can ask for his Facebook password if I ever feel the need to do so. I trust him and am not the snooping type and therefore I never asked him. Today however he gave me his password randomly. Now I feel obligated to give him my password as well, even thiugh he explicitly hasnt asked me for mine. I don't have anything to hide, but I feel sharing passwords can create unecessarry drama. How should I approach this.