What you are saying may be true about him; however, a lot of us can see the signs or beginning of trouble just from our past experience dealing with similar scenes.
Right now you are defending his actions - no matter what. Until YOU decide when you've had enough of his treatment, then you will continue to defend him. But don't be surprised that up the road things turn out what we've predicted (cheating, etc.)
It took me 14 yrs of my 17 yr marriage to my ex to really figure out I was being verbally/emotionally abused and to divorce him. I didn't have anyone/thing to compare until things really got bad. I happened to get a book out of the library (after hearing other stories of abuse and seeing SOME of the signs) - Abuse Survivors Speak Out - by Patricia Evans. THAT book saved my life, sanity, and helped me in so many ways to deal with abuse and get out. I cried reading that book cause all the "signs" had been there years before and I never saw them. I could have gotten out of the marriage way before I did. My son was 12 yrs old when I divorced and I really regret him seeing more then he should have regarding the abuse.
My ex hide a lot of things for many years and it is very tough to figure out verbal/emotional abuse compared to physical abuse.
Your bf does have a problem and if both of you don't address it soon, it will get worse. What happens when you find out that he is cheating on you? Next time he has too much, how do you know he won't be in someone else's bed having sex? Do you honestly expect him to tell you yes he is if you ask him? Wake up and smell the coffee - you're in denial right now.