Why can't I leave?

Ca

I'll try to make this short. I'm married. Been together 5 years. Starting in November of 2020 I realized I was unhappy with where I'm at and I think, who I'm with. My marriage started going downhill and has been a decline since. But everytime we get to the point of saying goodbye, I just can't seem to let go. I don't understand. Am I scared to be alone? Or on my own? I've never been on my own. I'm not sure. Maybe I think I don't deserve better.