Should I leave? Advice please…

*I’m so sorry in advance for the long post*

My fiancé and I have been together for 3 1/2 years. We have two boys together- one just turned two and the other is less than a month old. Before my oldest turned one, we moved out of state and away from my family to be closer to his family and I sold my car and quit my job to stay at home with our son (now sons) as that is what we both wanted. We don’t trust strangers with our kids and honestly don’t trust most of our family either. We just think our kids are best in my care instead of somebody else’s.

He has changed. A lot. We’re under a lot of stress financially (kind of his fault though because he won’t stop buying guns, knives, and tactical gear). He used to be the kind of father that would cry in the dark while rocking our oldest because he loved him so much, but I’ve noticed lately that he isn’t very nice most of the time. Every once in a while, he’ll take him out to the park or to his dad’s house and spend quality time with him. However, the majority of the time he will come home and just go to sleep on the couch. It’s so sad because my oldest waits all day for dad to be home and is SO excited when he walks in the door. My fiancé will say hi to him and sometimes give him a hug, but he’s so worried about trying to get a nap in that when my son is crawling on him trying to play with him, he will push him away or tell him to go away. He has stopped reading to him at night before bed when he does bedtime as well. He will rush his bedtime routine and is always looking for a reason to get him in bed quickly so that he can take a nap or play video games. He makes jokes about things that are just not funny at all- things that traumatized me as a child and make me so uncomfortable. I’ve expressed that they make me uncomfortable, he doesn’t care because he doesn’t stop doing it. A few days ago, I went to take a shower and could hear our newborn screaming. I tried to hurry, but my fiancé had come in and grabbed gas drops to give him. As I’m walking down the hallway to the living room where they are, I can hear that my newborns cries sound very muffled. Just as I’m turning the corner, I see him put his phone down on the couch behind him and pick up the baby. I called him out and asked if he was intentionally trying to muffle the baby’s cries and he said no that he had him doing tummy time… on a pile of blankets… I will say that I do have really bad PPA but it sounded like the baby was struggling to keep his face out of the blankets. I don’t want to think that this was intentional because he was very overstimulated and angry, but that’s definitely a thought in the back of my mind. He made a comment after I asked him if he was trying to quiet the baby that was something among the lines of, “If I wanted to kill him, I’d go get a gun from our room and kill all of us including myself.”

He and I don’t get along anymore either. He has said some very nasty and hurtful things to me and pretty much told me that he intentionally trapped me here in another state with no support system.

I don’t have my own money, I don’t have my own vehicle, and I am scared. I have no idea what to do. Part of me really thinks that I should leave and let him get his shit together, but I’m scared of the repercussions of that and his reaction to me leaving in general. Also, I’m worried that I’m overreacting and that me taking his kids away from him will push him into hurting himself and unnecessarily put myself and my two small children in poverty because I made an irrational decision. What should I do? What would you do?