I Don't Want to Die But I Don't Want to Live

I am really struggling. I am miserable in my marriage. I am miserable in my profession. I have not been suicidal in a couple of years, not since i started taking lithium regularly. I hate my life so much. I fucking hate my job - being a pharmacist is miserable fucking work. I am beholden to the government for unrealistic student loans and it is suffocating me. My marriage should be my happy place, my strength and my heart but its not. It just IS. We kind of exist. We say “i love you” at all the approprioate times but there is no passion, no feeling, no love making - not even just sex. We just exist. I love her and i dont know how long i can live like this. I have nothing in my life, except my son. He is the light in the darkness. He is my heart and my strength and he is why i dont take a lead sedative every single day. He is a good young man and i wont hurt him by killing myself or leaving his mother. I need to have something in my life to look forward to - i hate going to work and i hate going home after work. I have 1 hour driving without people hassling me each way. Thats all i have. Its so hard. I loved a woman, she is gone now, it kills me that she is gone. Why are we expected to just go on living when we are miserable? I dont understand why it isnt just ok to end it.