Feeling Lost

Can an adult run away? This is the question I’ve been pondering all day. I am only 25 and unhappy in my marriage. I feel like I’m failing my babies when they see me cry. I hate that they see their dad and I argue. I feel shame for it because I know it’s not what they deserve. If I leave will he be able to take care of them on his own. I feel like I would be better off dead but I’d rather just disappear and live a better life. Being lost and unloved and unhappy are things I want to leave behind me. How do I start.