What would you do??

In the beginning of our relationship,we promised there wouldn't be any lies or secrets and now I feel like this whole relationship was built on a lie. I've been noticing things that he does that made me question his sexuality. So one day I finally asked him and he said he was straight..but later on I heard him tell his brother he was bi but a week before that I heard him tell his friend he was gay mixed with bi(whatever that means)His ex boyfriend(I found out after he left that he was his ex) came over and while I was sitting on the couch,and my bf asked him (his ex)to make him some breakfast and he did.He made a big breakfast burrito for my bf and one for himself..mind you,there are 2 other people living in this house(including myself) and not once did we even get offered one. It's messed up how I gotta hear anything about my bf from his closest friend but when I ask him,he gets an attitude and walks away or leaves. Now I don't trust him like I use to bc if he's lying and hiding this,what else could he be lying and hiding?? I just don't know what to do anymore..when I try talking to him,when I ask him has he seen something that I'm searching for,he gets an attitude and then we get into an argument. I told him that I missed the old us and he just remained silent for a moment and then walked outta the room.