I hope that I am not breaking the rules by saying what I am about to say, but if I am, and it upsets anyone apart from OPs partner then my apologies, and please take it down.
OP, I presume that your partner is a manual labourer doing something equivalent to 10 or 11 hours down a mine hacking for coal (I know that thank God we don't have anyone in this country who does that anymore, but that he does something that is extremely hard physical work, with no breaks etc? I also assume that it is not something like working in his own shop, because to own a shop (or any business really) you need to have quite a lot of intelligence, and common sense, and your partner obviously has none.
He would need to know what products/produce sells well in the area he works in, he would need to understand how, why, and when he needed to order new stock, he would need to be aware of his storage facilities, both for how much he can store until it goes on to the shop floor, and whether it needs any special storage facilities, eg fridges, freezers, cold rooms etc. He would probably need to know how to employ at least one or two other people - and that in itself is a minefield, that I know very little about as I have never been in that position - but I expect that at the very least that they need a properly executed contract of employment, that will state their working hours, the type of things they are expected to do to fulfill their role, how much they get paid per hour, your partner's contribution to their pension, whether they get paid sick pay, and how much, and for how long (I naively thought that every person employed by someone else, got paid for their sick leave, someone who I am very close to told me recently that they didn't, and they are not self-employed - I was astounded). Then, of course, if your partner employs people, he will have to sort out all their tax returns etc, yes I presume that he could employ an accountant for that and all the other account issues to do with running a business, but I believe that many business owners prefer to do it themselves to save money, especially during the present and recent past, economic climate. Doing all of his own accounts could also go towards explaining why he is out of the house for 12 hours a day.
Your partner will also need to be 'personable' if he deals with either his own employees or customers, and obviously if he deals with both. If he doesn't know how to be polite and friendly with them he should very quickly find himself without both staff and customers. But being pleasant doesn't come naturally to your partner does it, he would have to work at it all day long at work, and I just can't see your partner being able to pull that off long term. So your partner can't need to employ people because his thoroughly obnoxious personality would not let him keep them. He can't run anything like even a small shop, because he hasn't shown any sign of actually having enough brain cells to achieve any of the necessary requirements to do so. His behaviour towards you shows a complete lack of both basic knowledge, and care, about how to treat another human being, let alone the person he is supposed to love even more than himself (sorry, but ha ha), the person he should respect and want the very best for, the person who in this case is also a mother to his first born, a mother to another one in her belly, you.
Even if your partner did work on a mine face, 12 hours a day and with no breaks, he should not expect you - who works 24 hours a day (even if some of that is 'on-call' duty) looking after the most precious things in the world, much more priceless than any gold in a gold mine, your and his children - to have a meal ready for him, a clean house,and ever open legs (another apology OP, one for my crudeness, and one for the vomit that just came into my mouth even contemplating having sex with someone who could look like a young Omar Shariff, but would make me feel violated if he came anywhere near me).
OP I assume that that awful prankster 'love', with the rose coloured spectacles, that he gives out to anyone eager to accept them - I am not insulting you here OP, in my younger days I have been known to wear those dazzling pink glasses, many of us otherwise intelligent and discerning women have fallen prisoner to those particular eye pieces - is what made you be with this semblance of a man, but I really hope that you have managed to take them off now, your thread suggests that you have? If you have discarded them, then I hope that the many great answers here by previous PPs, have helped you realise that: as you do all of the child care, all of the house care, nearly all of your partner's care, but very sadly hardly any of your own care, and that the only thing your partner provides is finance (and you even do part of that too), that you need to leave this parasite, this is not a symbiotic relationship, he brings you nothing but self doubt, heartache, and very hard work, and eventually he will do the same for your children.
I am so sorry if I am being too harsh on you here OP, that is definitely not my attention, hearing about your seemingly worthless partner, has left me feeling so angry at him, and with so much sympathy for you and your children, that I felt compelled to try to encourage you to leave him, or rather to throw him out if that is possible, and for you to realise that without him you will actually have less work to do, and much more happiness to savour.