Hei @lunarpoppies420, I hear you, it's very difficult to cope when people do not understand how you feel. I don't know your situation of course, but I would not say that your s/o doesn't try to understand. If he is not suicidal himself, he probably can't. People that have never had the idea to end their lives are unable to follow the logic, not because they don't try or don't want to or don't care about you, but simply because everything in their brain is wired towards making things better, and not towards ending it. In their logic, when dead, you can't make things better anymore. I think he might also be in a form of denial, he almost lost you, he was sensitive enough to pick up on what was going on and wanted to intervene and help you. I cannot imagine the fear he has gone though to try and catch you. To protect himself from being scared for you the whole time and just sitting on top of you to make sure you stay alive, he needs to go with the assumption that you will be alive when he comes back. I think otherwise, he wouldn't be able to leave you to go to work or get groceries etc etc.
It's difficult to foster mutual understanding, but it can be done if you communicate honestly and openly and if the other one is listening to the words of the other one and not to what s/he wants to hear. I'm sorry you feel so alone in this situation and that he isn't even trying to hear you, that must be super devastating. If you need someone to listen to you, please feel free to PM me.