Your H has gone to work and avoided the crisis, just as he avoided it last night and went to bed. He has lied to you over and over again and instead of staying to face the storm, he has changed his passwords and introduced even more secrecy.
This relationship is certainly not over with the OW. That is another lie.
I detest that he has seen this thread and read about all the blame you were putting on yourself for him falling out of love with you. I really, really want you to see that all those conversations you had with him ages ago about his "unhappiness" were all about setting you up to fail. It's astonishing how frequently this happens. I would be amazed if any of these conversations occurred before he had first contact with the OW and if you think back, I bet none of those conversations included what he would be doing to bring the intimacy and nurturing back into your relationship.
You have been given an utterly false script and unfortunately, because women are consistently fed this nonsense about men's needs and what will happen if we neglect them, you have been turning the screw inwards and berating yourself for being a nurturing mother who as a grown-up, suppressed her own needs in favour of her infants.
And your H has turned this horrible mantra and societal discourse against you, no doubt telling his idiot OW that his wife is child-obsessed, doesn't want sex and fails to give him enough attention and adoration.
I really want you to concentrate with all your muster on what you haven't been getting from your H, because the biggest myth is that affairs happen when someone hasn't been getting enough from their relationship. The truth is that this happened because he stopped giving to your relationship.
Now sometimes that lack of investment occurs before meeting an affair partner and if that was the case for your H. then he wouldn't have needed a very long permission-giving phase before he consented to an affair. However, in many cases, that under-investment is caused entirely by the prospect of an affair. Think back to when you last felt he was giving his all to this relationship and try to get at least one factual detail from this lying man - when he made first contact with this woman - not when the affair actually started.
This is terribly important, because if you've seen my other posts, you will know that I say there are two whole phases before a physical affair starts. The quicker the phases of mirroring/friendship and permission-giving, the more detached a person is before they move into the affair phase.
Above all, stop blaming yourself for any of this. Halt that false script now. I am relieved your anger has kicked in, it will serve you very well.
In practical terms, unless he starts telling the truth, confronting this and removing secrecy, I would insist that he leaves, but please get some RL help lined up, because it is totally unfair that you will be left with all the shitwork, especially when you are this traumatised and feel like you've been hit by a bus.