I (F34) came out as bisexual to my boyfriend (M41) and he's not taking it well

I've struggled with my sexuality for a long time, probably since my teenage years. I always just buried my head in the sand about it and then got with my boyfriend at 21. As far as I was concerned I was in a straight relationship and i've never even been with a woman, so there was no point in ever really acknowledging the fact that I wasn't 100% straight. Its only really in the last few years i've been able to admit it to myself.

Well in a stupid drunken moment I blurted out to my boyfriend that I think i'm bisexual. I broke down in tears and he dropped me off at my sisters to 'talk to her about it' and I was an emotional mess for the remainder of the night.

The next day we spoke about it and he seemed quite understanding. I tried to assure him that I love him and want to be with him and no-one else. He suggested that I should perhaps go and explore my sexuality but I told him thats not what I wanted.

He's being quite distant with me now. Left for work this morning without saying anything to me. I called him and asked if he was ok, he just said hes struggling to get his head around it and has been up all night thinking about it.

I don't really know what to do. I feel like i've completely messed up and wish I had never said anything. How can I make this right?