How do I save my relationship with my fiance?

Hi,So me and my fiance have been together 8 years and we have 4 children but they are not in our care due to past addictions but it is in the process of them being returned to us. My fiance hasn't let the past go, and that's what sets us off to arugments and fights. I have been sober for almost a year and am also pregnant with our 5th child. I am at the point where I am sick to death of fighting over past issues,and all I want is to move forward in life. I don't want to be bothered with the past and put under stress that I don't need to be in at this point in my pregnancy. All though I don't want to break off an 8 year relationship because I care so much about this man and I am willing to do councelling with him but he just dosen't want to do that. How can I talk him into trying to build a healthy relationship, rather than living in the past,because all that,s doing for us is bringing us down. I want to be a family again and really despertly want want to be happy once again.I need him to understand that I have made mistake in the past and so did he and I am ok with it and ready to move on in life. I love him more than anything. I am sad that he is still struggling to forgive&forget. I don't know how to help him,I tryed offering going to get couples councelling but he won,t go,so That makes things hard. I don't want to be fighting anylonger,I want him to realize that it hurts me and makes me sad that he thinks he can treat me this way after what we've been through together.What can I do to fix our relationship,I don't want it to end.I love him to much and can't see myself living without him. He packed a bag and left lastnight to his dad's and I am at home under alot of stress on the way he left things with me lastnight. I don't have family here to talk too,although he does and that is easyier for him. All I have is this computer and nobody to comfort me in this ruff time. I really need my fiance to come back and have a mature adult conversation with me rather than pointing his finger at me and blaming me for everything wrong that's happening in our relationsip.We used to be so happy and now it's hell and I hate it. He hasn't called me yet and it's been overnight since he left and I am afraid to call his dad's because he told me as he was leaving not to call him. It sounded like he broke it off lastnight but this isn't that 1st time this has happened, it's been going on for at least 3 months,he has left before and came back and just acted as if nothing happened. I am a reck right now and all I feel like doing is crying. Things seem to be getting worse every fight we have and I don't know what to do anymore, I feel like giving up at times but I care way to much for him. I miss him so much when he leaves like this,and not to mention,I'm scared to get a phone call from someone telling me he's been in a horrable accident,this is the kinda **** I don't want on my mind because when he's mad he tends to storm out and get behind the wheel and go get drunk and be stupid,and he dosn't know how to pick up the phone and call me and that sure makes me worry even more. So I need some advise on how to fix this relationship,what are some steps I can take or how can I get him to listen to me without him yelling at me. What are some ideas.Please I need some advise.Thanks so much!