I'm so unhappy in my relation ship - and its all my own fault (we have 2 children 2.5 yrs and 3 weeks old)

Well...my story is complex, but basically I am a relationship with a man that has deteriorated to constant bickering and nasty comments being exchanged between us 24/7. I can’t stand being around my partner. He has always been a 'joker / a CLOWN' but for the last few months I have found it difficult to tolerate ANY of his childish behavior. It just seems like there is NOTHING constructive or positive that comes out of his mouth at all.. Every thing is dribble; he zaps all of my energy. I hate the way I now constantly criticize him about almost everything, I can’t stand it. Also he has always been a drinker prior to him moving in with me about 5 years ago... but he slowed down to a carton of beer a week & also began to drink MID STRENGTH beer (at my request) now its a 36 can carton and its not even lasting the week. This last carton only lasted 4 days. Although he doesn’t get 'drunk' his drinking certainly affects his behavior and how he speaks to me - which he can’t see. HELP