New boyfriend tells me he's bisexual..

I recently just got into a relationship (boyfriend/girlfriend). I asked if there was anything I should know that he's into and he told me he is bi. I'm not sure how to ask questions, or how to deal with it. I've never felt that way toward women so I have no idea how that whole thing goes, I'm super monogamous but don't know how to ask his interpretation of being bi is or if him saying we are together is more of an "open" relationship.. this is all new to me but I really do care about him and want things to work out. ANY advice would be helpful!