Sorry that some people have jumped on you and are suggesting you don't want to spend time with your children, when you've made clear that you are their primary carer and you don't love your husband anymore. It shouldn't need stating that that is not the same as you don't love your children anymore, of course.
You must feel trapped. Noone wants to live with a partner who they don't love. I feel for you. And also for your husband who must also be hurt by this (I assume he's noticed!).
A couple of things spring to mind - firstly, some solo therapy might help you unpick your feelings. You mentioned the resentment that he didn't support you when you suffered with PND. It may be that his selfishness has impacted you and turned you 'off' him. When you better understand that, you can decide if he's basically a decent husband and father and it's worth making an effort or if, actually, there is more to this and you would be better off away from him.
Secondly - if he is basically a decent person who you've just fallen out of love with - please give it a chance before you leave him. I can't imagine how I would feel if my DH, who I love, told me he'd fallen out of love, wasn't sure why, but he wouldn't discuss it and give us the chance at least to try making it work. That wouldn't be fair.
If after therapy, if after talking to him and trying to understand what this is about and if it can helped, if then you feel more certain that you don't have a future, you will at least have tried.