Hi lapaull, I have no easy answers, I am in a similar place to you (without the children). When life feels intolerable it's hard to hang on. I try to remember that if I hurt myself I will probably harm those who care about me more than I can imagine. They need you for who you are. I try to remember a quote from a German thinker which roughly translates as ' When, through a person, a LITTLE more goodness and love,a LITTLE more light and truth come into the world, their life has had purpose' (capitals mine).
I hope I'm not just talking rubbish to you. My prayers are with you as we both try to find our way.