Doesn't matter now what he resents.
You need to start planning how you move in to a better future - asset split, where you each will live, how much you need to be earning to make this work. Part-time might not work for you - so you change it because of your own wants and needs, not because of what he might think (and bear in mind that he might be nasty about whatever you do, so it really isn't worth giving headspace to potential reactions)
And of course child arrangements. You can't force him to parent, but you can set the expectation that he will. So yes, put it to him that he's parent-in-charge EOW and one or two nights (and following morning school/nursery runs the next day). If he doesn't do it, at least you know where you stand. Do keep notes if he declines, and every time he flakes, just in case he plays silly buggers later.
Once you've started planning, and worked out how long each stage of the plan needs, you will feel a heck of a lot better, because you are taking back control.
In parallel, start doing stuff for yourself. Get a babysitter (so he can't flake and disrupt your plans) and go out. Anywhere, even if it's only to sit under a tree with a good book. Better still, meet new people, try new things. All terribly daunting when you're at low ebb - so baby steps are absolutely fine