I am sorry you are struggling with this. There's nothing wrong with keeping yourself safe by not coming out, but that doesn't do anything for the feeling of being trapped.
I'm not you, but i hope that you're able to find some space where you are able to be yourself, perhaps a friend group or an online support group?
Being alone and feeling abandoned by a partner is such a terrible feeling. Perhaps, since it all feels spiralling anyway, asking him bluntly for clarification, if you think he's gone it'll at least give you answers maybe?
There's not a magical set of words that will work for you, so throw away anything i have said that doesn't work. Most of all i wanted you to know people saw you and care you are in pain, even if they are just text on a screen. 💙