Hopefully, we've all got a long road ahead but as to whether it'll be lonely is a matter of personal choice. FWIW I don't have a live-in partner, I value the time I spend alone, and I never feel lonely.
Should anyone ask why you've split up, I suggest you use IB's words to tell them in a matter of fact manner. If they don't believe you that's their problem and you don't need to elaborate any further.
My fear for you is that controlling and abusive men rarely have the ability to let well alone and he may choose to return to the marital home without prior warning in the near future, particularly if he sees that you are coping perfectly well without him.
Please make an appointment asap with a rottweiler solicitor who specialises in divorce and family law and who offers a free half hour initial consultation. If you should need a recommendation or have any immediate questions, post on the Legal matters board.
If he should return you may need to seek an occupation order which will enable the police to remove him from your home and require him to stay away.
As for working, it's simply a question of getting yourself organised which it seems you should have done some time ago. You knew he couldn't be relied on and you could have taken steps to arrange the alternative childcare that you will need if you are to return to the workplace.
However, I would suggest you put thoughts of working on the back burner until you've got the formalities of ending your less than satisfactory marriage underway and the dc are settled into your new and happier way of life.
You'll find this board a great source of support and some here will become your friends in rl as well as in the virtual reality of the net.
Post on this thread whenever you feel the need and you'll be able to look back on it as you go along to see just how far you've come since you were able to get out from under his control.
In the meantime, have fun with your dc. Being able to please yourself without fear of censure from a controlling partner is liberating and, once you've experienced it to the full, you won't want to be a slave to any man again.