6yrs together but can't 'get' it together

Hi, my bf and I have been together 6yrs on and off, we have 2 boys 5&4. My problem is that we always argue over petty things that lead into yelling and just not very good behavior. We have been like this since our oldest turned one. He started to become this completely different person shortly before the baby was born, not working but never really being around. I never got too angry when addressing the issues until our 2nd son was born. We had moved close to my family to a state that offered decent pay and low living cost (the previous state / area our rent alone was 600$ a month, basic for a decent home in the area) , and the pay very low making 2500 a month together . We ended up back to previous area a year later. Argument continue because he would not get a steady job. He also didn't want me to work. We moved in with his grandparents where the arguments ebbed for awhile but the behavior continued. My best friend who lived 6-7 hrs away had her only brother pass away and he berated me when I begged to be with her. She ended up passing away 6weeks later and only because of his grandfather and aunt I was able to attend her funeral. His grandfather passed away 8 weeks after her. Everything went downhill hard. I went against him and got a job because he never had enough money to pay bills,even though he was making good money. He ended up draining everything his grandmother and I tried to save.I left him for 6months. Came back to try again. Exactly the same... I left again this past January because our arguments escalated to violence on my part towards him, we would cuss, call names and get pretty nasty in front of our kids and it has effected them tremendously. Our youngest yells at me and makes threats he doesn't understand because that is what he's grown up with. We decided to give it one last shot, and it's already back to the arguments. We have been back together for 2 months and have had 4 arguments that stemmed from 1) the president throwing a baseball like a girl (yeah ik, sad.) 2) our children telling me of a girlfriend he supposedly didn't have 3) him forgetting plans made 4) because he dropped chicken salad on the remote and it was my fault because I sat his sandwich too close to it. He ended this argument like the last taking about cheating and justifying his father cheating and almost killing his mother multiple times. I really don't understand at all because it all stars over minute things and ends up nasty. Any advice would be appreciated.

For the sake of the kids, you need to try and remove yourself from this situation. The kids need to be kids, not watch or hear all the fighting between you two. If they continue to see this they will think this is okay. Take a break away so that you can get some thing saved, focus on the kids, and heal from your broken grief. You never had time to greave your loved one and then took on more stress in your relationship. He needs to do the same and when you put your family back together make clear that from. Then on there will be peace in your home or you go for good. I faught with my kids dad but after a while I stopped cold. They don't remember us ever yelling or fighting. They just know I left at one point and we shared custody. Do more things for you and the kids. If you don't you will be depressed and no good to them or yourself. One day at a time make each day better and new. Hugs to you, and the kids. They need you