<human>: Can you give me the gist of the text in a nutshell?

When I first met my boyfriend in December 2013 we decided neither really wanted a serious relationship of any sorts and that we were both fine with casual dating (I had just broken up with my high school sweetheart; he had just graduated college and was "too focused on his career"). Casual dating to both of us really just meant hooking up and sexting. He confided in me about his occasional urges to sleep with men and visit glory holes to give head (which he had followed through on both numerous times). He also informed me that he has had sex with over two dozen people and casual encounters with numerous more. Not thinking he was going to be any sort of part of my life more than just a hook-up, I proceeded to tell my roommate; my roommate proceeded to tell everyone. 
However, we began to talk constantly and really connected. We never ironed out our actual relationship status; resulting in me royally screwing up and sleeping with my ex-something he considered cheating, and something I did not (I was under the impression that "casual" did not mean "committed"). After a short break we defined our relationship and things went forward full force. I decided to tell my older brother about my new boyfriend and how I think he might really have a huge part of my future, and learned that my brother had already heard about him and his sexual preferences from some mutual friends. I feel so incredibly guilty that I have betrayed his trust twice in such a short period of time. I guess I just want to know if theres any chance of this working, if I should be concerned about his previous sexual exploits, and if (and possibly how) I should tell him that nearly everyone in my life knows about his sex life that he tries to keep private. I'm incredibly worried that he won't forgive me a second time, which I would understand, but I've honestly never felt so connected to someone before. I've known him for four months, and he's become my best friend. I would hate to lose him from my life.
<bot>: I broke my boyfriend's trust (before we were dating) by letting it slip that he enjoys sleeping with men. I have no clue how to tell him without him hating me.